diff --git a/configs/freedom-k64f/README.txt b/configs/freedom-k64f/README.txt
index d72fae3f0b..1e23240fe0 100644
--- a/configs/freedom-k64f/README.txt
+++ b/configs/freedom-k64f/README.txt
@@ -973,4 +973,7 @@ Status
     USB device, however, has not yet been tested.  I have not yet looked
     into 48MHz clocking requirements.
 
- 
+  2017-02-10:  These have been numerous SDHC fixes submitted by Marc Rechte'.
+    These may or may not have fixed the SDHC issues mentioned about.  You
+    would have to retest to verify the SDHC functionality.
+
diff --git a/include/stdlib.h b/include/stdlib.h
index d10628ac41..0229bed72f 100644
--- a/include/stdlib.h
+++ b/include/stdlib.h
@@ -203,7 +203,9 @@ long double strtold(FAR const char *str, FAR char **endptr);
 #ifdef CONFIG_HAVE_LONG_LONG
 #define atoll(nptr) strtoll((nptr), NULL, 10)
 #endif
+#ifdef CONFIG_HAVE_DOUBLE
 #define atof(nptr)  strtod((nptr), NULL)
+#endif
 
 /* Binary to string conversions */
 
diff --git a/libc/Kconfig b/libc/Kconfig
index 8988dc3696..407e9dead7 100644
--- a/libc/Kconfig
+++ b/libc/Kconfig
@@ -5,865 +5,20 @@
 
 comment "Standard C Library Options"
 
-config STDIO_DISABLE_BUFFERING
-	bool "Disable STDIO Buffering"
-	default n
-	---help---
-		Tiny systems may need to disable all support for I/O buffering in
-		order to minimize the memory footprint.
-
-		NOTE that even if STDIO buffering is enabled, you can still disable
-		buffering by setting CONFIG_STDIO_BUFFER_SIZE=0 or dynamically
-		through the setvbuf() interface.  In this case, however,  memory
-		used for buffering will be eliminated, of course, but there will be
-		no reduction in static code size.  Only setting
-		CONFIG_STDIO_DISABLE_BUFFERING will reduce static code size.
-
-		The setvbuf() interface is not available if
-		CONFIG_STDIO_DISABLE_BUFFERING is selected.
-
-if !STDIO_DISABLE_BUFFERING
-
-config STDIO_BUFFER_SIZE
-	int "STDIO buffer size"
-	default 64
-	---help---
-		Size of buffers using within the C buffered I/O interfaces (printf,
-		putchar, fwrite, etc.).  This function sets the initial I/O buffer
-		size.  Zero disables I/O buffering initially.  Any buffer size may
-		be subsequently modified using setvbuf().
-
-config STDIO_LINEBUFFER
-	bool "STDIO line buffering"
-	default y
-	---help---
-		Sets the default behavior to flush buffered I/O whenever a newline
-		character is found in the output data stream.  This setting just
-		sets the initial default behavior of all streams.  The behavior of
-		an individual stream can be changed via setvbuf().
-
-endif # !STDIO_DISABLE_BUFFERING
-
-config NUNGET_CHARS
-	int "Number unget() characters"
-	default 2
-	---help---
-		Number of characters that can be buffered by ungetc() (Only if NFILE_STREAMS > 0)
-
-config LIB_HOMEDIR
-	string "Home directory"
-	default "/"
-	depends on !DISABLE_ENVIRON
-	---help---
-		The home directory to use with operations like such as 'cd ~'
-
-source libc/dllfcn/Kconfig
-source libc/modlib/Kconfig
+source libc/stdio/Kconfig
 source libc/math/Kconfig
 source libc/machine/Kconfig
-
-config NOPRINTF_FIELDWIDTH
-	bool "Disable sprintf support fieldwidth"
-	default n
-	---help---
-		sprintf-related logic is a little smaller if we do not support field
-		widths.
-
-config LIBC_FLOATINGPOINT
-	bool "Enable floating point in printf"
-	default n
-	---help---
-		By default, floating point
-		support in printf, sscanf, etc. is disabled.
-
-config LIBC_LONG_LONG
-	bool "Enable long long support in printf"
-	default y if !DEFAULT_SMALL
-	default n if DEFAULT_SMALL
-	---help---
-		Enables support for long long formats in printf, sscanf, etc. is
-		enabled.  This is enabled by default but if you are trying to
-		reduce the FLASH footprint, then disabling this feature is one
-		option.  The FLASH saves comes not from disabling the long long
-		formats, but rather from omitting the large long long arithmetic
-		libraries that will be drawn into the build if long long support
-		is enabled.
-
-config LIBC_SCANSET
-	bool "Scanset support"
-	default n
-	---help---
-		Add scanset support to sscanf().
-
-config LIBC_IOCTL_VARIADIC
-	bool "Enable variadic ioctl()"
-	default n
-	---help---
-		By default, NuttX implements the "old style," three-parameter,
-		ioctl() interface with this function prototype:
-
-			int ioctl(int fd, int req, unsigned long arg);
-
-		That function is implemented as part of the VFS.  If
-		LIBC_IOCTL_VARIADIC is selected, then an additional compatibility
-		layer will be provided in the C library.  The enabled, then function
-		prototype will become:
-
-			int ioctl(int fd, int req, ...);
-
-		The ioctl() is not controlled by any standard so it is really
-		arbitrary which format you used.  You may select the variadic
-		function prototype with this option.  That will slightly increase
-		code size and ioctl() processing time.  It will not support a
-		variable number of arguments and it still always expects to see a
-		third argument of type 'unsigned long'.  The only benefit of this
-		alternative function signature is that it may provide greater
-		compatibility if you are porting code from other platforms that use
-		the variadic ioctl() function.
-
-		WARNING:  Use of this option could cause subtle system errors is
-		the third argument is omitted or if the sizeof the thread argument
-		is anything other than sizeof (unsigned long).  Most small integers
-		will be promoted to 'int'.  The following assertion appears in ioctl():
-
-			DEBUGASSERT(sizeof(int)        == sizeof(unsigned long) &&
-			            sizeof(FAR void *) == sizeof(unsigned long));
-
-		Do not enable this option if the above is not true.  32-bit ARM
-		should pass this test with all three types having sizeof(type) == 4
-		bytes.  'float' should also be tested.  But 'long long' and 'double'
-		are out of the question!  Don't event try to pass them.
-
-		And what will happen if no third argument is passed?  In most cases,
-		this should just result in a garbage value for arg.  But you may
-		discover cases where something worse happens!
-
-config LIBC_WCHAR
-	bool "Enable wide-characters (Unicode) support"
-	default n
-	---help---
-		By default, wide-characters support is disabled.
-
-config LIBC_LOCALE
-	bool "Enable I18N (LOCALE) support"
-	default n
-	---help---
-		By default, i18n (locale) support is disabled.
-
-config LIB_RAND_ORDER
-	int "Order of the random number generate"
-	default 1
-	range 1 3
-	---help---
-		The order of the random number generator. 1=fast but very bad random
-		numbers, 3=slow but very good random numbers.
-
-choice
-	prompt "Newline Options"
-	default EOL_IS_EITHER_CRLF
-	---help---
-		This selection determines the line terminating character that is used.
-		Some environments may return CR as end-of-line, others LF, and others
-		both.  If not specified, the default is either CR or LF (but not both)
-		as the line terminating charactor.
-
-config EOL_IS_CR
-	bool "EOL is CR"
-
-config EOL_IS_LF
-	bool "EOL is LF"
-
-config EOL_IS_BOTH_CRLF
-	bool "EOL is CR and LF"
-
-config EOL_IS_EITHER_CRLF
-	bool "EOL is CR or LF"
-
-endchoice
-
-config LIBC_EXECFUNCS
-	bool "Enable exec[l|v] / posix_spawn() Support"
-	default n
-	depends on !BINFMT_DISABLE
-	---help---
-		Enable support for the exec[l|v] family of functions that can be
-		used to start other programs, terminating the current program and
-		the posix_spawn() familty of functions that can be used start other
-		programs without terminating the current program.  The typical
-		usage of the exec[l|v] functions is (1) first call vfork() to create
-		a new thread, then (2) call exec[l|v] to replace the new thread with
-		a program from the file system.
-
-		NOTE 1: This two step process start is completely unnecessary in
-		NuttX and is provided only for compatibily with Unix systems.  These
-		functions are essentially just wrapper functions that (1) call the
-		non-standard binfmt function 'exec', and then (2) exit(0).  Since
-		the new thread will be terminated by the exec[l|v] call, it really
-		served no purpose other than to suport Unix compatility.
-
-		The posix_spawn() functions do not have this inefficiency.
-
-		NOTE 2: Support for exec[l|v] and posix_spawn() is conditional
-		because they require additional support for symbol tables that
-		will not be available in the typical system.
-
-if LIBC_EXECFUNCS
-
-config EXECFUNCS_HAVE_SYMTAB
-	bool "Have symbol table"
-	default n if BUILD_KERNEL
-	default y if !BUILD_KERNEL
-	---help---
-		If you have a system symbol table, then you must select this
-		option in order to use it.  Symbol tables are required in most
-		cases in order to like executable programs to the base code.
-
-if EXECFUNCS_HAVE_SYMTAB
-config EXECFUNCS_SYMTAB
-	string "Symbol table used by exec[l|v]"
-	default "g_symtab"
-	---help---
-		The exec[l|v] and posix_spawn() functions are wrapper functions that
-		call the non-standard binfmt function 'exec').  The binfmt
-		function 'exec' needs to have (1) a symbol table that provides the
-		list of symbols exported by the base code, and (2) the number of
-		symbols in that table.  This selection provides the name of that
-		symbol table.
-
-config EXECFUNCS_NSYMBOLS
-	int "Number of Symbols in the Table"
-	default 0
-	---help---
-		The exec[l|v] and posix_spawn() functions are wrapper functions that
-		call the non-standard binfmt function 'exec').  The binfmt
-		function 'exec' needs to have (1) a symbol table that provides the
-		list of symbols exported by the base code, and (2) the number of
-		symbols in that table.  This selection provides the number of
-		symbols in the symbol table.
-
-endif # EXECFUNCS_HAVE_SYMTAB
-endif # LIBC_EXECFUNCS
-
-config POSIX_SPAWN_PROXY_STACKSIZE
-	int "Spawn Stack Size"
-	default 1024
-	---help---
-		If posix_spawn[p]() and task_spawn() use I/O redirection options,
-		they will require an intermediary/proxy task to muck with the file
-		descriptors.  This configuration item specifies the stack size
-		used for the proxy. Default: 1024 bytes.
-
-config TASK_SPAWN_DEFAULT_STACKSIZE
-	int "Default task_spawn Stack Size"
-	default 2048
-	depends on !ARCH_ADDRENV
-	---help---
-		The actual size to use for the child task's stack can be set with
-		task_spawnattr_setstacksize().  This value specifies the default
-		stack size to use if task_spawnattr_setstacksize() is not used.
-		Default: 2048.
-
-config LIBC_STRERROR
-	bool "Enable strerror"
-	default n
-	---help---
-		strerror() is useful because it decodes 'errno' values into a human readable
-		strings.  But it can also require a lot of memory.  If this option is selected,
-		strerror() will still exist in the build but it will not decode error values.
-		This option should be used by other logic to decide if it should use strerror()
-		or not.  For example, the NSH application will not use strerror() if this
-		option is not selected; perror() will not use strerror() is this option is not
-		selected (see also NSH_STRERROR).
-
-config LIBC_STRERROR_SHORT
-	bool "Use short error descriptions in strerror()"
-	default n
-	depends on LIBC_STRERROR
-	---help---
-		If this option is selected, then strerror() will use a shortened string when
-		it decodes the error.  Specifically, strerror() is simply use the string that
-		is the common name for the error.  For example, the 'errno' value of 2 will
-		produce the string "No such file or directory" is LIBC_STRERROR_SHORT
-		is not defined but the string "ENOENT" is LIBC_STRERROR_SHORT is defined.
-
-config LIBC_PERROR_STDOUT
-	bool "perror() to stdout"
-	default n
-	---help---
-		POSIX requires that perror() provide its output on stderr.  This option may
-		be defined, however, to provide perror() output that is serialized with
-		other stdout messages.
-
-config LIBC_TMPDIR
-	string "Temporary file directory"
-	default "/tmp"
-	depends on FS_WRITABLE
-		---help---
-		If a write-able file system is selected, this string will be
-		provided to specify the full path to a directory where temporary
-		files can be created.  This would be a good application of RAM disk:
-		To provide temporary storage for application data.
-
-config LIBC_MAX_TMPFILE
-	int "Maximum size of a temporary file path"
-	default 32
-	depends on FS_WRITABLE
-		---help---
-		If a write-able file system is selected, then temporary file may be
-		supported at the path provided by LIBC_TMPDIR.  The tmpnam() interface
-		keeps a static copy of this last filename produced; this value is the
-		maximum size of that last filename.  This size is the size of the full
-		file path.
-
-config ARCH_LOWPUTC
-	bool "Low-level console output"
-	default "y"
-	---help---
-		architecture supports low-level, boot time console output
-
-config LIBC_LOCALTIME
-	bool "localtime API call support"
-	default "n"
-	depends on !DISABLE_ENVIRON
-	---help---
-		localtime API call support
-
-		Logic currently depends on file system support with, at a minimum, these
-		files in the zoneinfo directory:  GMT and posixrules.  An additional
-		timezone file is required for any additional, local time zone(s) and the
-		environment variable TZ must be set to the name of that timezone file
-		when tzset() is called.
-
-		See https://www.iana.org/time-zones .  See also nuttx/zoneinfo
-		which provides a framework for incorporating the TZ database into a
-		NuttX build.
-
-if LIBC_LOCALTIME
-
-config LIBC_TZ_MAX_TIMES
-	int "Maximum number of times in timezone"
-	default 370
-	---help---
-		Timezone files with more than this number of times will not be usedi
-		(tmecnt).
-
-		Warning: Some files in IANA TZ database include many times.  The current
-		posixrules file, for example, has timecnt = 236.  The value of
-		TX_MAX_ITMES in the tzfile.h header file on my Linux system is 370, the
-		default used here.  You may want to reduce this value for a smaller
-		footprint.
-
-config LIBC_TZ_MAX_TYPES
-	int "Maximum number of TZ types"
-	default 20
-	---help---
-		Maximum number of local time types.  You may want to reduce this value
-		for a smaller footprint.
-
-config LIBC_TZDIR
-	string "zoneinfo directory path"
-	default "/etc/zoneinfo"
-	---help---
-		This is the full path to the location where the TZ database is expected
-		to be found.
-
-config LIB_ZONEINFO
-	bool "TZ database"
-	default n
-	---help---
-		Download and build the TZ/Olson database.
-
-if LIB_ZONEINFO
-
-config LIB_ZONEINFO_ROMFS
-	bool "Build ROMFS filesystem"
-	default n
-	depends on FS_ROMFS
-	---help---
-		Build a mountable ROMFS filesystem containing the TZ/Olson database
-
-endif # LIB_ZONEINFO
-endif # LIBC_LOCALTIME
-
-config TIME_EXTENDED
-	bool "Add day of week, year support"
-	default "n"
-	depends on !LIBC_LOCALTIME
-	---help---
-		Selecting TIME_EXTENDED adds tm_wday, tm_yday and tm_isdst
-		to the tm struct. This allows integration with 3rd party libraries
-		that expect the tm struct to contain these members.
-
-		Note: tm_isdst is always 0
-
-config LIB_SENDFILE_BUFSIZE
-	int "sendfile() buffer size"
-	default 512
-	---help---
-		Size of the I/O buffer to allocate in sendfile().  Default: 512b
-
-config ARCH_ROMGETC
-	bool "Support for ROM string access"
-	default n
-	---help---
-		In Harvard architectures, data accesses and instruction accesses
-		occur on different buses, perhaps concurrently.  All data accesses
-		are performed on the data bus unless special machine instructions
-		are used to read data from the instruction address space.  Also, in
-		the typical MCU, the available SRAM data memory is much smaller that
-		the non-volatile FLASH instruction memory.  So if the application
-		requires many constant strings, the only practical solution may be
-		to store those constant strings in FLASH memory where they can only
-		be accessed using architecture-specific machine instructions.
-
-		If ARCH_ROMGETC is defined, then the architecture logic must export
-		the function up_romgetc().  up_romgetc() will simply read one byte
-		of data from the instruction space.
-
-		If ARCH_ROMGETC is selected, certain C stdio functions are effected: (1)
-		All format strings in printf, fprintf, sprintf, etc. are assumed to lie
-		in FLASH (string arguments for %s are still assumed to reside in SRAM).
-		And (2), the string argument to puts and fputs is assumed to reside
-		in FLASH.  Clearly, these assumptions may have to modified for the
-		particular needs of your environment.  There is no "one-size-fits-all"
-		solution for this problem.
-
-config MEMCPY_VIK
-	bool "Vik memcpy()"
-	default n
-	depends on !LIBC_ARCH_MEMCPY
-	---help---
-		Select this option to use the optimized memcpy() function by Daniel Vik.
-		Select this option for improved performance at the expense of increased
-		size. See licensing information in the top-level COPYING file.
-
-if MEMCPY_VIK
-
-config MEMCPY_PRE_INC_PTRS
-	bool "Pre-increment pointers"
-	default n
-	---help---
-		Use pre-increment of pointers. Default is post increment of pointers.
-
-config MEMCPY_INDEXED_COPY
-	bool "Array indexing"
-	default y
-	---help---
-		Copying data using array indexing. Using this option, disables the
-		MEMCPY_PRE_INC_PTRS option.
-
-config MEMCPY_64BIT
-	bool "64-bit memcpy()"
-	default n
-	---help---
-		Compiles memcpy() for architectures that suppport 64-bit operations
-		efficiently.
-
-endif # MEMCPY_VIK
-
-config MEMSET_OPTSPEED
-	bool "Optimize memset() for speed"
-	default n
-	depends on !LIBC_ARCH_MEMSET
-	---help---
-		Select this option to use a version of memcpy() optimized for speed.
-		Default: memcpy() is optimized for size.
-
-config MEMSET_64BIT
-	bool "64-bit memset()"
-	default n
-	depends on MEMSET_OPTSPEED
-	---help---
-		Compiles memset() for architectures that suppport 64-bit operations
-		efficiently.
-
-config ARCH_HAVE_TLS
-	bool
-	default n
-	---help---
-		Selected by the configuration system if the current architecture
-		supports TLS.
-
-menuconfig TLS
-	bool "Thread Local Storage (TLS)"
-	default n
-	depends on ARCH_HAVE_TLS
-	---help---
-		Build in support for stack based thread local storage (TLS).
-
-if TLS
-
-config TLS_LOG2_MAXSTACK
-	int "Maximum stack size (log2)"
-	default 13
-	range 11 24
-	---help---
-		Stack based TLS works by fetch thread information from the beginning
-		of the stack memory allocation.  In order to do this, the memory
-		must be aligned in such a way that the executing logic can simply
-		masking the current stack pointer to get the beginning of the stack
-		allocation.
-
-		This setting specifies the alignment of the stack as a power of 2:
-		11=2KB, 12=4KB, 13=8KB, etc.  The exact alignment is not so critical
-		except that (1) a very large value can cause you to run out of
-		alignable memory (and fail memory allocations), and (2) smaller
-		values will limit the maximum size of the stack (hence the naming
-		of this configuration value).
-
-config TLS_NELEM
-	int "Number of TLS elements"
-	default 1
-	---help---
-		The number of unique TLS elements.  These can be accessed with
-		the user library functions tls_get_element() and tls_set_element().
-
-endif # TLS
-
-config LIBC_IPv4_ADDRCONV
-	bool "IPv4 address conversions"
-	default n
-	depends on !NET_IPv4
-
-config LIBC_IPv6_ADDRCONV
-	bool "IPv6 address conversions"
-	default n
-	depends on !NET_IPv6
-
-config LIBC_NETDB
-	bool
-	default n
-
-menuconfig NETDB_HOSTFILE
-	bool "Network host file support"
-	default n
-	depends on FS_READABLE
-	select LIBC_NETDB
-	---help---
-		Enable network host table look ups via gethostbyname() and
-		gethostbyaddr().
-
-if NETDB_HOSTFILE
-
-config NETDB_HOSTCONF_PATH
-	string "Path to host configuration file"
-	default "/etc/hosts"
-
-config NETDB_MAX_ALTNAMES
-	int "Max number of alternate host names"
-	default 4
-
-config NETDB_BUFSIZE
-	int "gethostname() buffer size"
-	default 128
-
-endif # NETDB_HOSTFILE
-
-menuconfig NETDB_DNSCLIENT
-	bool "DNS Name resolution"
-	default n
-	depends on NET && NET_UDP
-	select LIBC_NETDB
-	---help---
-		Enable support for the name resolution; Enable network host
-		resolution via gethostbyname().
-
-if NETDB_DNSCLIENT
-
-config NETDB_DNSCLIENT_ENTRIES
-	int "Number of DNS resolver entries"
-	default 0 if DEFAULT_SMALL
-	default 8 if !DEFAULT_SMALL
-	range 0 255
-	---help---
-		Number of cached DNS resolver entries.  Default: 8.  Zero disables
-		all cached name resolutions.
-
-		Disabling the DNS cache means that each access call to
-		gethostbyname() will result in a new DNS network query.  If
-		CONFIG_NETDB_DNSCLIENT_ENTRIES is non-zero, then entries will be
-		cached and if the name mapping can be found in that cache, the
-		network query can be avoid.  Of course, this is only useful if you
-		query the same name often and if the IP address of the name is
-		stable.  If the IP address can change, then cachin DNS address
-		might have undesirable side-effects (see help for
-		CONFIG_NETDB_DNSCLIENT_LIFESEC).
-
-config NETDB_DNSCLIENT_NAMESIZE
-	int "Max size of a cached hostname"
-	default 32
-	---help---
-		The size of a hostname string in the DNS resolver cache is fixed.
-		This setting provides the maximum size of a hostname.  Names longer
-		than this will be aliased!  Default: 32
-
-config NETDB_DNSCLIENT_LIFESEC
-	int "Life of a DNS cache entry (seconds)"
-	default 3600
-	---help---
-		Cached entries in the name resolution cache older than this will not
-		be used.  Default: 1 hour.  Zero means that entries will not expire.
-
-		Small values of CONFIG_NETDB_DNSCLIENT_LIFESEC may result in more
-		network DNS queries; larger values can make a host unreachable for
-		the entire duration of the timeout value.  This might happen, for
-		example, if the remote host was assigned a different IP address by
-		a DHCP server.
-
-config NETDB_DNSCLIENT_MAXRESPONSE
-	int "Max response size"
-	default 96
-	---help---
-		This setting determines the maximum size of response message that
-		can be received by the DNS resolver.  The default is 96 but may
-		need to be larger on enterprise networks (perhaps 176).
-
-
-config NETDB_RESOLVCONF
-	bool "DNS resolver file support"
-	default n
-	depends on FS_READABLE
-	---help---
-		Enable DNS server look ups in resolver file like /etc/resolv.conf.
-
-if NETDB_RESOLVCONF
-
-config NETDB_RESOLVCONF_PATH
-	string "Path to host configuration file"
-	default "/etc/resolv.conf"
-
-config NETDB_RESOLVCONF_NONSTDPORT
-	bool "Non-standard port support"
-	default n
-	---help---
-		By default, the resolv.conf file will hold only records like:
-
-			nameserver xx.xx.xx.xx
-			nameserver xxxx:::::::xxxx
-
-		The default port of 53 is always assumed.
-
-		If this option is selected, then OpenBSD style resolv.conf files
-		will be supported.  This adds logic for a bracket port notation
-		like:
-
-			nameserver [xx.xx.xx.xx]:ppppp
-			nameserver [xxxx:::::::xxxx]:ppppp
-
-endif # NETDB_RESOLVCONF
-
-choice
-	prompt "DNS server address type"
-	default NETDB_DNSSERVER_IPv4 if NET_IPv4
-	default NETDB_DNSSERVER_IPv6 if !NET_IPv4 && NET_IPv6
-	default NETDB_DNSSERVER_NOADDR if !NET_IPv4 && !NET_IPv6
-	depends on !NETDB_RESOLVCONF
-
-config NETDB_DNSSERVER_NOADDR
-	bool "No default DNS server address"
-	---help---
-		There is not default DNS nameserver address.  Application must call
-		dns_add_server() at runtime to add the DNS server address.
-
-config NETDB_DNSSERVER_IPv4
-	bool "IPv4 DNS server address"
-	depends on NET_IPv4
-	---help---
-		An IPv4 default DNS nameserver address will be provided.  Application
-		may overwrite this start default server address by calling
-		dns_add_server() at runtime.
-
-config NETDB_DNSSERVER_IPv6
-	bool "IPv6 DNS server address"
-	depends on NET_IPv6
-	---help---
-		An IPv6 default DNS nameserver address will be provided.  Application
-		may overwrite this start default server address by calling
-		dns_add_server() at runtime.
-
-endchoice # DNS server address type
-
-config NETDB_DNSSERVER_IPv4ADDR
-	hex "Target IPv4 address"
-	default 0x0a000001
-	depends on NETDB_DNSSERVER_IPv4
-	---help---
-		Default DNS server IPv4 address in host byte order.  Default value
-		10.0.0.0.1.  This may be changed via dns_add_nameserver().
-
-if NETDB_DNSSERVER_IPv6
-
-config NETDB_DNSSERVER_IPv6ADDR_1
-	hex "[0]"
-	default 0xfc00
-	range 0x0 0xffff
-	---help---
-		This is the default IP address of the DNS server.  This is a 16-bit
-		integer value in host order.  Each of the eight values forming the
-		full IPv6 address must be specified individually.  This is the first
-		of the 8-values.  The default for all eight values is fc00::1.
-
-config NETDB_DNSSERVER_IPv6ADDR_2
-	hex "[1]"
-	default 0x0000
-	range 0x0 0xffff
-	---help---
-		This is the default IP address of the DNS server.  This is a 16-bit
-		integer value in host order.  Each of the eight values forming the
-		full IPv6 address must be specified individually.  This is the second
-		of the 8-values.  The default for all eight values is fc00::1.
-
-config NETDB_DNSSERVER_IPv6ADDR_3
-	hex "[2]"
-	default 0x0000
-	range 0x0 0xffff
-	---help---
-		This is the default IP address of the DNS server.  This is a 16-bit
-		integer value in host order.  Each of the eight values forming the
-		full IPv6 address must be specified individually.  This is the third
-		of the 8-values.  The default for all eight values is fc00::1.
-
-config NETDB_DNSSERVER_IPv6ADDR_4
-	hex "[3]"
-	default 0x0000
-	range 0x0 0xffff
-	---help---
-		This is the default IP address of the DNS server.  This is a 16-bit
-		integer value in host order.  Each of the eight values forming the
-		full IPv6 address must be specified individually.  This is the fourth
-		of the 8-values.  The default for all eight values is fc00::1.
-
-config NETDB_DNSSERVER_IPv6ADDR_5
-	hex "[4]"
-	default 0x0000
-	range 0x0 0xffff
-	---help---
-		This is the default IP address of the DNS server.  This is a 16-bit
-		integer value in host order.  Each of the eight values forming the
-		full IPv6 address must be specified individually.  This is the fifth
-		of the 8-values.  The default for all eight values is fc00::1.
-
-config NETDB_DNSSERVER_IPv6ADDR_6
-	hex "[5]"
-	default 0x0000
-	range 0x0 0xffff
-	---help---
-		This is the default IP address of the DNS server.  This is a 16-bit
-		integer value in host order.  Each of the eight values forming the
-		full IPv6 address must be specified individually.  This is the sixth
-		of the 8-values.  The default for all eight values is fc00::1.
-
-config NETDB_DNSSERVER_IPv6ADDR_7
-	hex "[6]"
-	default 0x0000
-	range 0x0 0xffff
-	---help---
-		This is the default IP address of the DNS server.  This is a 16-bit
-		integer value in host order.  Each of the eight values forming the
-		full IPv6 address must be specified individually.  This is the seventh
-		of the 8-values.  The default for all eight values is fc00::1.
-
-config NETDB_DNSSERVER_IPv6ADDR_8
-	hex "[7]"
-	default 0x0001
-	range 0x0 0xffff
-	---help---
-		This is the default IP address of the DNS server.  This is a 16-bit
-		integer value in host order.  Each of the eight values forming the
-		full IPv6 address must be specified individually.  This is the last
-		of the 8-values.  The default for all eight values is fc00::1.
-
-endif # NETDB_DNSSERVER_IPv6
-endif # NETDB_DNSCLIENT
-
-comment "Non-standard Library Support"
-
-config LIB_CRC64_FAST
-	bool "Fast CRC64"
-	default n
-	---help---
-		Enable the CRC64 lookup table to compute the CRC64 faster.
-
-if BUILD_PROTECTED || BUILD_KERNEL
-
-config LIB_USRWORK
-	bool "User mode worker thread"
-	default n
-	depends on !DISABLE_SIGNALS
-	---help---
-		User space work queues can also be made available for deferred
-		processing in the NuttX kernel build.
-
-if LIB_USRWORK
-
-config LIB_USRWORKPRIORITY
-	int "User mode priority worker thread priority"
-	default 100
-	---help---
-		The execution priority of the user-mode priority worker thread.  Default: 100
-
-config LIB_USRWORKPERIOD
-	int "User mode worker thread period"
-	default 100000
-	---help---
-		How often the lower priority worker thread checks for work in units
-		of microseconds. Default: 100*1000 (100 MS).
-
-config LIB_USRWORKSTACKSIZE
-	int "User mode worker thread stack size"
-	default 2048
-	---help---
-		The stack size allocated for the lower priority worker thread.  Default: 2K.
-
-endif # LIB_USRWORK
-endif # BUILD_PROTECTED || BUILD_KERNEL
-
-config LIB_KBDCODEC
-	bool "Keyboard CODEC"
-	default n
-	---help---
-		In NuttX, a keyboard/keypad driver is simply a character driver that
-		may have an (optional) encoding/decoding layer on the data returned
-		by the character driver. A keyboard may return simple text data
-		(alphabetic, numeric, and punctuaction) or control characters
-		(enter, control-C, etc.).  However, in addition, most keyboards
-		support actions that cannot be represented as text data. Such
-		actions include things like cursor controls (home, up arrow,
-		page down, etc.), editing functions (insert, delete, etc.), volume
-		controls, (mute, volume up, etc.) and other special functions.
-		Some special encoding may be required to multiplex these two classes
-		of data.
-
-		This option enables the functions that implement the encoding and
-		decoding of keyboard data.  These are the interfaces prototyped in
-		include/nuttx/input/kbd_codec.h.  While not correctly a part of
-		the C library, it is included here because the decoding side of this
-		interface must be accessible by end user programs.
-
-config LIB_SLCDCODEC
-	bool "Segment LCD CODEC"
-	default n
-	---help---
-		In NuttX, a character-oriented, segment LCD (SLCD) driver is simply
-		a character device that may have an (optional) encoding/decoding
-		layer on the data provided to the SLCD driver.  The application may
-		provide simple text data (alphabetic, numeric, and punctuaction) or
-		control characters (enter, control-C, etc.).  However, in addition,
-		most SLCDs support actions that cannot be represented as text data.
-		Such actions include things like cursor controls (home, up arrow,
-		page down, etc.) and other special functions (e.g., blinking).  Some
-		special encoding may be required to multiplex these two classes of
-		data.
-
-		This option enables the functions that implement the encoding and
-		decoding of SLCD data.  These are the interfaces prototyped in
-		include/nuttx/lcd/slcd_codec.h.  While not correctly a part of the C
-		library, it is included here because the encoding side of this
-		interface must be accessible by end user programs.
-
-config LIB_HEX2BIN
-	bool "Intel HEX to binary conversion library"
-	default n
-	---help---
-		Build in support for conversions from Intel Hex format to binary.
-		This selection enables the interfaces of include/hex2bin.h.
+source libc/stdlib/Kconfig
+source libc/unistd/Kconfig
+source libc/string/Kconfig
+source libc/dllfcn/Kconfig
+source libc/modlib/Kconfig
+source libc/wchar/Kconfig
+source libc/locale/Kconfig
+source libc/time/Kconfig
+source libc/tls/Kconfig
+source libc/net/Kconfig
+source libc/netdb/Kconfig
+source libc/misc/Kconfig
+source libc/wqueue/Kconfig
+source libc/hex2bin/Kconfig
diff --git a/libc/dllfcn/Kconfig b/libc/dllfcn/Kconfig
index 7fce284ed6..738251a4e1 100644
--- a/libc/dllfcn/Kconfig
+++ b/libc/dllfcn/Kconfig
@@ -3,6 +3,8 @@
 # see the file kconfig-language.txt in the NuttX tools repository.
 #
 
+comment "Shared Library Support"
+
 config LIBC_DLLFCN
 	bool "Shared library support"
 	default n
diff --git a/libc/hex2bin/Kconfig b/libc/hex2bin/Kconfig
new file mode 100644
index 0000000000..10eadd6bc9
--- /dev/null
+++ b/libc/hex2bin/Kconfig
@@ -0,0 +1,182 @@
+#
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+comment "Standard C Library Options"
+
+config STDIO_DISABLE_BUFFERING
+	bool "Disable STDIO Buffering"
+	default n
+	---help---
+		Tiny systems may need to disable all support for I/O buffering in
+		order to minimize the memory footprint.
+
+		NOTE that even if STDIO buffering is enabled, you can still disable
+		buffering by setting CONFIG_STDIO_BUFFER_SIZE=0 or dynamically
+		through the setvbuf() interface.  In this case, however,  memory
+		used for buffering will be eliminated, of course, but there will be
+		no reduction in static code size.  Only setting
+		CONFIG_STDIO_DISABLE_BUFFERING will reduce static code size.
+
+		The setvbuf() interface is not available if
+		CONFIG_STDIO_DISABLE_BUFFERING is selected.
+
+if !STDIO_DISABLE_BUFFERING
+
+config STDIO_BUFFER_SIZE
+	int "STDIO buffer size"
+	default 64
+	---help---
+		Size of buffers using within the C buffered I/O interfaces (printf,
+		putchar, fwrite, etc.).  This function sets the initial I/O buffer
+		size.  Zero disables I/O buffering initially.  Any buffer size may
+		be subsequently modified using setvbuf().
+
+config STDIO_LINEBUFFER
+	bool "STDIO line buffering"
+	default y
+	---help---
+		Sets the default behavior to flush buffered I/O whenever a newline
+		character is found in the output data stream.  This setting just
+		sets the initial default behavior of all streams.  The behavior of
+		an individual stream can be changed via setvbuf().
+
+endif # !STDIO_DISABLE_BUFFERING
+
+config NUNGET_CHARS
+	int "Number unget() characters"
+	default 2
+	---help---
+		Number of characters that can be buffered by ungetc() (Only if NFILE_STREAMS > 0)
+
+source libc/math/Kconfig
+source libc/machine/Kconfig
+source libc/stdlib/Kconfig
+source libc/unistd/Kconfig
+source libc/string/Kconfig
+source libc/dllfcn/Kconfig
+source libc/modlib/Kconfig
+
+config NOPRINTF_FIELDWIDTH
+	bool "Disable sprintf support fieldwidth"
+	default n
+	---help---
+		sprintf-related logic is a little smaller if we do not support field
+		widths.
+
+config LIBC_FLOATINGPOINT
+	bool "Enable floating point in printf"
+	default n
+	---help---
+		By default, floating point
+		support in printf, sscanf, etc. is disabled.
+
+config LIBC_LONG_LONG
+	bool "Enable long long support in printf"
+	default y if !DEFAULT_SMALL
+	default n if DEFAULT_SMALL
+	---help---
+		Enables support for long long formats in printf, sscanf, etc. is
+		enabled.  This is enabled by default but if you are trying to
+		reduce the FLASH footprint, then disabling this feature is one
+		option.  The FLASH saves comes not from disabling the long long
+		formats, but rather from omitting the large long long arithmetic
+		libraries that will be drawn into the build if long long support
+		is enabled.
+
+config LIBC_SCANSET
+	bool "Scanset support"
+	default n
+	---help---
+		Add scanset support to sscanf().
+
+source libc/wchar/Kconfig
+source libc/locale/Kconfig
+
+choice
+	prompt "Newline Options"
+	default EOL_IS_EITHER_CRLF
+	---help---
+		This selection determines the line terminating character that is used.
+		Some environments may return CR as end-of-line, others LF, and others
+		both.  If not specified, the default is either CR or LF (but not both)
+		as the line terminating charactor.
+
+config EOL_IS_CR
+	bool "EOL is CR"
+
+config EOL_IS_LF
+	bool "EOL is LF"
+
+config EOL_IS_BOTH_CRLF
+	bool "EOL is CR and LF"
+
+config EOL_IS_EITHER_CRLF
+	bool "EOL is CR or LF"
+
+endchoice
+
+source libc/time/Kconfig
+
+config MEMCPY_VIK
+	bool "Vik memcpy()"
+	default n
+	depends on !LIBC_ARCH_MEMCPY
+	---help---
+		Select this option to use the optimized memcpy() function by Daniel Vik.
+		Select this option for improved performance at the expense of increased
+		size. See licensing information in the top-level COPYING file.
+
+if MEMCPY_VIK
+
+config MEMCPY_PRE_INC_PTRS
+	bool "Pre-increment pointers"
+	default n
+	---help---
+		Use pre-increment of pointers. Default is post increment of pointers.
+
+config MEMCPY_INDEXED_COPY
+	bool "Array indexing"
+	default y
+	---help---
+		Copying data using array indexing. Using this option, disables the
+		MEMCPY_PRE_INC_PTRS option.
+
+config MEMCPY_64BIT
+	bool "64-bit memcpy()"
+	default n
+	---help---
+		Compiles memcpy() for architectures that suppport 64-bit operations
+		efficiently.
+
+endif # MEMCPY_VIK
+
+config MEMSET_OPTSPEED
+	bool "Optimize memset() for speed"
+	default n
+	depends on !LIBC_ARCH_MEMSET
+	---help---
+		Select this option to use a version of memcpy() optimized for speed.
+		Default: memcpy() is optimized for size.
+
+config MEMSET_64BIT
+	bool "64-bit memset()"
+	default n
+	depends on MEMSET_OPTSPEED
+	---help---
+		Compiles memset() for architectures that suppport 64-bit operations
+		efficiently.
+
+source libc/tls/Kconfig
+source libc/net/Kconfig
+source libc/netdb/Kconfig
+source libc/misc/Kconfig
+source libc/wqueue/Kconfig
+
+config LIB_HEX2BIN
+	bool "Intel HEX to binary conversion library"
+	default n
+	---help---
+		Build in support for conversions from Intel Hex format to binary.
+		This selection enables the interfaces of include/hex2bin.h.
diff --git a/libc/locale/Kconfig b/libc/locale/Kconfig
new file mode 100644
index 0000000000..74fd56f9fa
--- /dev/null
+++ b/libc/locale/Kconfig
@@ -0,0 +1,12 @@
+#
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+comment "Locale Support"
+
+config LIBC_LOCALE
+	bool "Enable I18N (LOCALE) support"
+	default n
+	---help---
+		By default, i18n (locale) support is disabled.
diff --git a/libc/machine/Kconfig b/libc/machine/Kconfig
index 7620774c44..8d2be70beb 100644
--- a/libc/machine/Kconfig
+++ b/libc/machine/Kconfig
@@ -7,6 +7,43 @@
 # specific implementations.  Not all architectures support implementations
 # for every library function.
 
+comment "Architecture-Specific Spport"
+
+config ARCH_LOWPUTC
+	bool "Low-level console output"
+	default "y"
+	---help---
+		architecture supports low-level, boot time console output
+
+config ARCH_ROMGETC
+	bool "Support for ROM string access"
+	default n
+	---help---
+		In Harvard architectures, data accesses and instruction accesses
+		occur on different buses, perhaps concurrently.  All data accesses
+		are performed on the data bus unless special machine instructions
+		are used to read data from the instruction address space.  Also, in
+		the typical MCU, the available SRAM data memory is much smaller that
+		the non-volatile FLASH instruction memory.  So if the application
+		requires many constant strings, the only practical solution may be
+		to store those constant strings in FLASH memory where they can only
+		be accessed using architecture-specific machine instructions.
+
+		If ARCH_ROMGETC is defined, then the architecture logic must export
+		the function up_romgetc().  up_romgetc() will simply read one byte
+		of data from the instruction space.
+
+		If ARCH_ROMGETC is selected, certain C stdio functions are effected: (1)
+		All format strings in printf, fprintf, sprintf, etc. are assumed to lie
+		in FLASH (string arguments for %s are still assumed to reside in SRAM).
+		And (2), the string argument to puts and fputs is assumed to reside
+		in FLASH.  Clearly, these assumptions may have to modified for the
+		particular needs of your environment.  There is no "one-size-fits-all"
+		solution for this problem.
+
+# Default settings for C library functions that may be replaced with
+# architecture-specific versions.
+
 config LIBC_ARCH_MEMCPY
 	bool
 	default n
diff --git a/libc/math/Kconfig b/libc/math/Kconfig
index a3a859824e..8da47fdfb2 100644
--- a/libc/math/Kconfig
+++ b/libc/math/Kconfig
@@ -3,6 +3,8 @@
 # see the file kconfig-language.txt in the NuttX tools repository.
 #
 
+comment "Math Library Support"
+
 config LIBM
 	bool "Standard Math library"
 	default n
diff --git a/libc/misc/Kconfig b/libc/misc/Kconfig
new file mode 100644
index 0000000000..8c917f0348
--- /dev/null
+++ b/libc/misc/Kconfig
@@ -0,0 +1,104 @@
+#
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+config LIBC_IOCTL_VARIADIC
+	bool "Enable variadic ioctl()"
+	default n
+	---help---
+		By default, NuttX implements the "old style," three-parameter,
+		ioctl() interface with this function prototype:
+
+			int ioctl(int fd, int req, unsigned long arg);
+
+		That function is implemented as part of the VFS.  If
+		LIBC_IOCTL_VARIADIC is selected, then an additional compatibility
+		layer will be provided in the C library.  The enabled, then function
+		prototype will become:
+
+			int ioctl(int fd, int req, ...);
+
+		The ioctl() is not controlled by any standard so it is really
+		arbitrary which format you used.  You may select the variadic
+		function prototype with this option.  That will slightly increase
+		code size and ioctl() processing time.  It will not support a
+		variable number of arguments and it still always expects to see a
+		third argument of type 'unsigned long'.  The only benefit of this
+		alternative function signature is that it may provide greater
+		compatibility if you are porting code from other platforms that use
+		the variadic ioctl() function.
+
+		WARNING:  Use of this option could cause subtle system errors is
+		the third argument is omitted or if the sizeof the thread argument
+		is anything other than sizeof (unsigned long).  Most small integers
+		will be promoted to 'int'.  The following assertion appears in ioctl():
+
+			DEBUGASSERT(sizeof(int)        == sizeof(unsigned long) &&
+			            sizeof(FAR void *) == sizeof(unsigned long));
+
+		Do not enable this option if the above is not true.  32-bit ARM
+		should pass this test with all three types having sizeof(type) == 4
+		bytes.  'float' should also be tested.  But 'long long' and 'double'
+		are out of the question!  Don't event try to pass them.
+
+		And what will happen if no third argument is passed?  In most cases,
+		this should just result in a garbage value for arg.  But you may
+		discover cases where something worse happens!
+
+config LIB_SENDFILE_BUFSIZE
+	int "sendfile() buffer size"
+	default 512
+	---help---
+		Size of the I/O buffer to allocate in sendfile().  Default: 512b
+
+comment "Non-standard Library Support"
+
+config LIB_CRC64_FAST
+	bool "Fast CRC64"
+	default n
+	---help---
+		Enable the CRC64 lookup table to compute the CRC64 faster.
+
+config LIB_KBDCODEC
+	bool "Keyboard CODEC"
+	default n
+	---help---
+		In NuttX, a keyboard/keypad driver is simply a character driver that
+		may have an (optional) encoding/decoding layer on the data returned
+		by the character driver. A keyboard may return simple text data
+		(alphabetic, numeric, and punctuaction) or control characters
+		(enter, control-C, etc.).  However, in addition, most keyboards
+		support actions that cannot be represented as text data. Such
+		actions include things like cursor controls (home, up arrow,
+		page down, etc.), editing functions (insert, delete, etc.), volume
+		controls, (mute, volume up, etc.) and other special functions.
+		Some special encoding may be required to multiplex these two classes
+		of data.
+
+		This option enables the functions that implement the encoding and
+		decoding of keyboard data.  These are the interfaces prototyped in
+		include/nuttx/input/kbd_codec.h.  While not correctly a part of
+		the C library, it is included here because the decoding side of this
+		interface must be accessible by end user programs.
+
+config LIB_SLCDCODEC
+	bool "Segment LCD CODEC"
+	default n
+	---help---
+		In NuttX, a character-oriented, segment LCD (SLCD) driver is simply
+		a character device that may have an (optional) encoding/decoding
+		layer on the data provided to the SLCD driver.  The application may
+		provide simple text data (alphabetic, numeric, and punctuaction) or
+		control characters (enter, control-C, etc.).  However, in addition,
+		most SLCDs support actions that cannot be represented as text data.
+		Such actions include things like cursor controls (home, up arrow,
+		page down, etc.) and other special functions (e.g., blinking).  Some
+		special encoding may be required to multiplex these two classes of
+		data.
+
+		This option enables the functions that implement the encoding and
+		decoding of SLCD data.  These are the interfaces prototyped in
+		include/nuttx/lcd/slcd_codec.h.  While not correctly a part of the C
+		library, it is included here because the encoding side of this
+		interface must be accessible by end user programs.
diff --git a/libc/modlib/Kconfig b/libc/modlib/Kconfig
index eeb5d05dcc..9980795f1b 100644
--- a/libc/modlib/Kconfig
+++ b/libc/modlib/Kconfig
@@ -3,6 +3,8 @@
 # see the file kconfig-language.txt in the NuttX tools repository.
 #
 
+comment "Module Library Configuration"
+
 config LIBC_MODLIB
 	bool
 	default n
diff --git a/libc/net/Kconfig b/libc/net/Kconfig
new file mode 100644
index 0000000000..1fc85b7c5d
--- /dev/null
+++ b/libc/net/Kconfig
@@ -0,0 +1,16 @@
+#
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+comment "Standard C Library Options"
+
+config LIBC_IPv4_ADDRCONV
+	bool "IPv4 address conversions"
+	default n
+	depends on !NET_IPv4
+
+config LIBC_IPv6_ADDRCONV
+	bool "IPv6 address conversions"
+	default n
+	depends on !NET_IPv6
diff --git a/libc/netdb/Kconfig b/libc/netdb/Kconfig
new file mode 100644
index 0000000000..aed5b09f3c
--- /dev/null
+++ b/libc/netdb/Kconfig
@@ -0,0 +1,252 @@
+#
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+comment "NETDB Support"
+
+config LIBC_NETDB
+	bool
+	default n
+
+menuconfig NETDB_HOSTFILE
+	bool "Network host file support"
+	default n
+	depends on FS_READABLE
+	select LIBC_NETDB
+	---help---
+		Enable network host table look ups via gethostbyname() and
+		gethostbyaddr().
+
+if NETDB_HOSTFILE
+
+config NETDB_HOSTCONF_PATH
+	string "Path to host configuration file"
+	default "/etc/hosts"
+
+config NETDB_MAX_ALTNAMES
+	int "Max number of alternate host names"
+	default 4
+
+config NETDB_BUFSIZE
+	int "gethostname() buffer size"
+	default 128
+
+endif # NETDB_HOSTFILE
+
+menuconfig NETDB_DNSCLIENT
+	bool "DNS Name resolution"
+	default n
+	depends on NET && NET_UDP
+	select LIBC_NETDB
+	---help---
+		Enable support for the name resolution; Enable network host
+		resolution via gethostbyname().
+
+if NETDB_DNSCLIENT
+
+config NETDB_DNSCLIENT_ENTRIES
+	int "Number of DNS resolver entries"
+	default 0 if DEFAULT_SMALL
+	default 8 if !DEFAULT_SMALL
+	range 0 255
+	---help---
+		Number of cached DNS resolver entries.  Default: 8.  Zero disables
+		all cached name resolutions.
+
+		Disabling the DNS cache means that each access call to
+		gethostbyname() will result in a new DNS network query.  If
+		CONFIG_NETDB_DNSCLIENT_ENTRIES is non-zero, then entries will be
+		cached and if the name mapping can be found in that cache, the
+		network query can be avoid.  Of course, this is only useful if you
+		query the same name often and if the IP address of the name is
+		stable.  If the IP address can change, then cachin DNS address
+		might have undesirable side-effects (see help for
+		CONFIG_NETDB_DNSCLIENT_LIFESEC).
+
+config NETDB_DNSCLIENT_NAMESIZE
+	int "Max size of a cached hostname"
+	default 32
+	---help---
+		The size of a hostname string in the DNS resolver cache is fixed.
+		This setting provides the maximum size of a hostname.  Names longer
+		than this will be aliased!  Default: 32
+
+config NETDB_DNSCLIENT_LIFESEC
+	int "Life of a DNS cache entry (seconds)"
+	default 3600
+	---help---
+		Cached entries in the name resolution cache older than this will not
+		be used.  Default: 1 hour.  Zero means that entries will not expire.
+
+		Small values of CONFIG_NETDB_DNSCLIENT_LIFESEC may result in more
+		network DNS queries; larger values can make a host unreachable for
+		the entire duration of the timeout value.  This might happen, for
+		example, if the remote host was assigned a different IP address by
+		a DHCP server.
+
+config NETDB_DNSCLIENT_MAXRESPONSE
+	int "Max response size"
+	default 96
+	---help---
+		This setting determines the maximum size of response message that
+		can be received by the DNS resolver.  The default is 96 but may
+		need to be larger on enterprise networks (perhaps 176).
+
+
+config NETDB_RESOLVCONF
+	bool "DNS resolver file support"
+	default n
+	depends on FS_READABLE
+	---help---
+		Enable DNS server look ups in resolver file like /etc/resolv.conf.
+
+if NETDB_RESOLVCONF
+
+config NETDB_RESOLVCONF_PATH
+	string "Path to host configuration file"
+	default "/etc/resolv.conf"
+
+config NETDB_RESOLVCONF_NONSTDPORT
+	bool "Non-standard port support"
+	default n
+	---help---
+		By default, the resolv.conf file will hold only records like:
+
+			nameserver xx.xx.xx.xx
+			nameserver xxxx:::::::xxxx
+
+		The default port of 53 is always assumed.
+
+		If this option is selected, then OpenBSD style resolv.conf files
+		will be supported.  This adds logic for a bracket port notation
+		like:
+
+			nameserver [xx.xx.xx.xx]:ppppp
+			nameserver [xxxx:::::::xxxx]:ppppp
+
+endif # NETDB_RESOLVCONF
+
+choice
+	prompt "DNS server address type"
+	default NETDB_DNSSERVER_IPv4 if NET_IPv4
+	default NETDB_DNSSERVER_IPv6 if !NET_IPv4 && NET_IPv6
+	default NETDB_DNSSERVER_NOADDR if !NET_IPv4 && !NET_IPv6
+	depends on !NETDB_RESOLVCONF
+
+config NETDB_DNSSERVER_NOADDR
+	bool "No default DNS server address"
+	---help---
+		There is not default DNS nameserver address.  Application must call
+		dns_add_server() at runtime to add the DNS server address.
+
+config NETDB_DNSSERVER_IPv4
+	bool "IPv4 DNS server address"
+	depends on NET_IPv4
+	---help---
+		An IPv4 default DNS nameserver address will be provided.  Application
+		may overwrite this start default server address by calling
+		dns_add_server() at runtime.
+
+config NETDB_DNSSERVER_IPv6
+	bool "IPv6 DNS server address"
+	depends on NET_IPv6
+	---help---
+		An IPv6 default DNS nameserver address will be provided.  Application
+		may overwrite this start default server address by calling
+		dns_add_server() at runtime.
+
+endchoice # DNS server address type
+
+config NETDB_DNSSERVER_IPv4ADDR
+	hex "Target IPv4 address"
+	default 0x0a000001
+	depends on NETDB_DNSSERVER_IPv4
+	---help---
+		Default DNS server IPv4 address in host byte order.  Default value
+		10.0.0.0.1.  This may be changed via dns_add_nameserver().
+
+if NETDB_DNSSERVER_IPv6
+
+config NETDB_DNSSERVER_IPv6ADDR_1
+	hex "[0]"
+	default 0xfc00
+	range 0x0 0xffff
+	---help---
+		This is the default IP address of the DNS server.  This is a 16-bit
+		integer value in host order.  Each of the eight values forming the
+		full IPv6 address must be specified individually.  This is the first
+		of the 8-values.  The default for all eight values is fc00::1.
+
+config NETDB_DNSSERVER_IPv6ADDR_2
+	hex "[1]"
+	default 0x0000
+	range 0x0 0xffff
+	---help---
+		This is the default IP address of the DNS server.  This is a 16-bit
+		integer value in host order.  Each of the eight values forming the
+		full IPv6 address must be specified individually.  This is the second
+		of the 8-values.  The default for all eight values is fc00::1.
+
+config NETDB_DNSSERVER_IPv6ADDR_3
+	hex "[2]"
+	default 0x0000
+	range 0x0 0xffff
+	---help---
+		This is the default IP address of the DNS server.  This is a 16-bit
+		integer value in host order.  Each of the eight values forming the
+		full IPv6 address must be specified individually.  This is the third
+		of the 8-values.  The default for all eight values is fc00::1.
+
+config NETDB_DNSSERVER_IPv6ADDR_4
+	hex "[3]"
+	default 0x0000
+	range 0x0 0xffff
+	---help---
+		This is the default IP address of the DNS server.  This is a 16-bit
+		integer value in host order.  Each of the eight values forming the
+		full IPv6 address must be specified individually.  This is the fourth
+		of the 8-values.  The default for all eight values is fc00::1.
+
+config NETDB_DNSSERVER_IPv6ADDR_5
+	hex "[4]"
+	default 0x0000
+	range 0x0 0xffff
+	---help---
+		This is the default IP address of the DNS server.  This is a 16-bit
+		integer value in host order.  Each of the eight values forming the
+		full IPv6 address must be specified individually.  This is the fifth
+		of the 8-values.  The default for all eight values is fc00::1.
+
+config NETDB_DNSSERVER_IPv6ADDR_6
+	hex "[5]"
+	default 0x0000
+	range 0x0 0xffff
+	---help---
+		This is the default IP address of the DNS server.  This is a 16-bit
+		integer value in host order.  Each of the eight values forming the
+		full IPv6 address must be specified individually.  This is the sixth
+		of the 8-values.  The default for all eight values is fc00::1.
+
+config NETDB_DNSSERVER_IPv6ADDR_7
+	hex "[6]"
+	default 0x0000
+	range 0x0 0xffff
+	---help---
+		This is the default IP address of the DNS server.  This is a 16-bit
+		integer value in host order.  Each of the eight values forming the
+		full IPv6 address must be specified individually.  This is the seventh
+		of the 8-values.  The default for all eight values is fc00::1.
+
+config NETDB_DNSSERVER_IPv6ADDR_8
+	hex "[7]"
+	default 0x0001
+	range 0x0 0xffff
+	---help---
+		This is the default IP address of the DNS server.  This is a 16-bit
+		integer value in host order.  Each of the eight values forming the
+		full IPv6 address must be specified individually.  This is the last
+		of the 8-values.  The default for all eight values is fc00::1.
+
+endif # NETDB_DNSSERVER_IPv6
+endif # NETDB_DNSCLIENT
diff --git a/libc/stdio/Kconfig b/libc/stdio/Kconfig
new file mode 100644
index 0000000000..7b897caa89
--- /dev/null
+++ b/libc/stdio/Kconfig
@@ -0,0 +1,118 @@
+#
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+comment "Standard C I/O"
+
+config STDIO_DISABLE_BUFFERING
+	bool "Disable STDIO Buffering"
+	default n
+	---help---
+		Tiny systems may need to disable all support for I/O buffering in
+		order to minimize the memory footprint.
+
+		NOTE that even if STDIO buffering is enabled, you can still disable
+		buffering by setting CONFIG_STDIO_BUFFER_SIZE=0 or dynamically
+		through the setvbuf() interface.  In this case, however,  memory
+		used for buffering will be eliminated, of course, but there will be
+		no reduction in static code size.  Only setting
+		CONFIG_STDIO_DISABLE_BUFFERING will reduce static code size.
+
+		The setvbuf() interface is not available if
+		CONFIG_STDIO_DISABLE_BUFFERING is selected.
+
+if !STDIO_DISABLE_BUFFERING
+
+config STDIO_BUFFER_SIZE
+	int "STDIO buffer size"
+	default 64
+	---help---
+		Size of buffers using within the C buffered I/O interfaces (printf,
+		putchar, fwrite, etc.).  This function sets the initial I/O buffer
+		size.  Zero disables I/O buffering initially.  Any buffer size may
+		be subsequently modified using setvbuf().
+
+config STDIO_LINEBUFFER
+	bool "STDIO line buffering"
+	default y
+	---help---
+		Sets the default behavior to flush buffered I/O whenever a newline
+		character is found in the output data stream.  This setting just
+		sets the initial default behavior of all streams.  The behavior of
+		an individual stream can be changed via setvbuf().
+
+endif # !STDIO_DISABLE_BUFFERING
+
+config NUNGET_CHARS
+	int "Number unget() characters"
+	default 2
+	---help---
+		Number of characters that can be buffered by ungetc() (Only if NFILE_STREAMS > 0)
+
+config NOPRINTF_FIELDWIDTH
+	bool "Disable sprintf support fieldwidth"
+	default n
+	---help---
+		sprintf-related logic is a little smaller if we do not support field
+		widths.
+
+config LIBC_FLOATINGPOINT
+	bool "Enable floating point in printf"
+	default n
+	---help---
+		By default, floating point
+		support in printf, sscanf, etc. is disabled.
+
+config LIBC_LONG_LONG
+	bool "Enable long long support in printf"
+	default y if !DEFAULT_SMALL
+	default n if DEFAULT_SMALL
+	---help---
+		Enables support for long long formats in printf, sscanf, etc. is
+		enabled.  This is enabled by default but if you are trying to
+		reduce the FLASH footprint, then disabling this feature is one
+		option.  The FLASH saves comes not from disabling the long long
+		formats, but rather from omitting the large long long arithmetic
+		libraries that will be drawn into the build if long long support
+		is enabled.
+
+config LIBC_SCANSET
+	bool "Scanset support"
+	default n
+	---help---
+		Add scanset support to sscanf().
+
+choice
+	prompt "Newline Options"
+	default EOL_IS_EITHER_CRLF
+	---help---
+		This selection determines the line terminating character that is used.
+		Some environments may return CR as end-of-line, others LF, and others
+		both.  If not specified, the default is either CR or LF (but not both)
+		as the line terminating charactor.
+
+config EOL_IS_CR
+	bool "EOL is CR"
+
+config EOL_IS_LF
+	bool "EOL is LF"
+
+config EOL_IS_BOTH_CRLF
+	bool "EOL is CR and LF"
+
+config EOL_IS_EITHER_CRLF
+	bool "EOL is CR or LF"
+
+endchoice
+
+source libc/time/Kconfig
+
+config MEMCPY_VIK
+	bool "Vik memcpy()"
+	default n
+	depends on !LIBC_ARCH_MEMCPY
+	---help---
+		Select this option to use the optimized memcpy() function by Daniel Vik.
+		Select this option for improved performance at the expense of increased
+		size. See licensing information in the top-level COPYING file.
diff --git a/libc/stdlib/Kconfig b/libc/stdlib/Kconfig
new file mode 100644
index 0000000000..138022811b
--- /dev/null
+++ b/libc/stdlib/Kconfig
@@ -0,0 +1,47 @@
+#
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+comment "Random Number Generation"
+
+config LIB_RAND_ORDER
+	int "Order of the random number generate"
+	default 1
+	range 1 3
+	---help---
+		The order of the random number generator. 1=fast but very bad random
+		numbers, 3=slow but very good random numbers.
+
+comment "Environment Variables"
+
+config LIB_HOMEDIR
+	string "Home directory"
+	default "/"
+	depends on !DISABLE_ENVIRON
+	---help---
+		The home directory to use with operations like such as 'cd ~'
+
+comment "Temporary Files"
+
+config LIBC_TMPDIR
+	string "Temporary file directory"
+	default "/tmp"
+	depends on FS_WRITABLE
+		---help---
+		If a write-able file system is selected, this string will be
+		provided to specify the full path to a directory where temporary
+		files can be created.  This would be a good application of RAM disk:
+		To provide temporary storage for application data.
+
+config LIBC_MAX_TMPFILE
+	int "Maximum size of a temporary file path"
+	default 32
+	depends on FS_WRITABLE
+		---help---
+		If a write-able file system is selected, then temporary file may be
+		supported at the path provided by LIBC_TMPDIR.  The tmpnam() interface
+		keeps a static copy of this last filename produced; this value is the
+		maximum size of that last filename.  This size is the size of the full
+		file path.
+
diff --git a/libc/string/Kconfig b/libc/string/Kconfig
new file mode 100644
index 0000000000..deb01c4988
--- /dev/null
+++ b/libc/string/Kconfig
@@ -0,0 +1,89 @@
+#
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+comment "errno Decode Support"
+
+config LIBC_STRERROR
+	bool "Enable strerror"
+	default n
+	---help---
+		strerror() is useful because it decodes 'errno' values into a human readable
+		strings.  But it can also require a lot of memory.  If this option is selected,
+		strerror() will still exist in the build but it will not decode error values.
+		This option should be used by other logic to decide if it should use strerror()
+		or not.  For example, the NSH application will not use strerror() if this
+		option is not selected; perror() will not use strerror() is this option is not
+		selected (see also NSH_STRERROR).
+
+config LIBC_STRERROR_SHORT
+	bool "Use short error descriptions in strerror()"
+	default n
+	depends on LIBC_STRERROR
+	---help---
+		If this option is selected, then strerror() will use a shortened string when
+		it decodes the error.  Specifically, strerror() is simply use the string that
+		is the common name for the error.  For example, the 'errno' value of 2 will
+		produce the string "No such file or directory" is LIBC_STRERROR_SHORT
+		is not defined but the string "ENOENT" is LIBC_STRERROR_SHORT is defined.
+
+config LIBC_PERROR_STDOUT
+	bool "perror() to stdout"
+	default n
+	---help---
+		POSIX requires that perror() provide its output on stderr.  This option may
+		be defined, however, to provide perror() output that is serialized with
+		other stdout messages.
+
+comment "memcpy/memset Options"
+
+config MEMCPY_VIK
+	bool "Vik memcpy()"
+	default n
+	depends on !LIBC_ARCH_MEMCPY
+	---help---
+		Select this option to use the optimized memcpy() function by Daniel Vik.
+		Select this option for improved performance at the expense of increased
+		size. See licensing information in the top-level COPYING file.
+
+if MEMCPY_VIK
+
+config MEMCPY_PRE_INC_PTRS
+	bool "Pre-increment pointers"
+	default n
+	---help---
+		Use pre-increment of pointers. Default is post increment of pointers.
+
+config MEMCPY_INDEXED_COPY
+	bool "Array indexing"
+	default y
+	---help---
+		Copying data using array indexing. Using this option, disables the
+		MEMCPY_PRE_INC_PTRS option.
+
+config MEMCPY_64BIT
+	bool "64-bit memcpy()"
+	default n
+	---help---
+		Compiles memcpy() for architectures that suppport 64-bit operations
+		efficiently.
+
+endif # MEMCPY_VIK
+
+config MEMSET_OPTSPEED
+	bool "Optimize memset() for speed"
+	default n
+	depends on !LIBC_ARCH_MEMSET
+	---help---
+		Select this option to use a version of memcpy() optimized for speed.
+		Default: memcpy() is optimized for size.
+
+config MEMSET_64BIT
+	bool "64-bit memset()"
+	default n
+	depends on MEMSET_OPTSPEED
+	---help---
+		Compiles memset() for architectures that suppport 64-bit operations
+		efficiently.
+
diff --git a/libc/time/Kconfig b/libc/time/Kconfig
new file mode 100644
index 0000000000..c3d806bc00
--- /dev/null
+++ b/libc/time/Kconfig
@@ -0,0 +1,81 @@
+#
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+comment "Time/Time Zone Support"
+
+config LIBC_LOCALTIME
+	bool "localtime API call support"
+	default "n"
+	depends on !DISABLE_ENVIRON
+	---help---
+		localtime API call support
+
+		Logic currently depends on file system support with, at a minimum, these
+		files in the zoneinfo directory:  GMT and posixrules.  An additional
+		timezone file is required for any additional, local time zone(s) and the
+		environment variable TZ must be set to the name of that timezone file
+		when tzset() is called.
+
+		See https://www.iana.org/time-zones .  See also nuttx/zoneinfo
+		which provides a framework for incorporating the TZ database into a
+		NuttX build.
+
+if LIBC_LOCALTIME
+
+config LIBC_TZ_MAX_TIMES
+	int "Maximum number of times in timezone"
+	default 370
+	---help---
+		Timezone files with more than this number of times will not be usedi
+		(tmecnt).
+
+		Warning: Some files in IANA TZ database include many times.  The current
+		posixrules file, for example, has timecnt = 236.  The value of
+		TX_MAX_ITMES in the tzfile.h header file on my Linux system is 370, the
+		default used here.  You may want to reduce this value for a smaller
+		footprint.
+
+config LIBC_TZ_MAX_TYPES
+	int "Maximum number of TZ types"
+	default 20
+	---help---
+		Maximum number of local time types.  You may want to reduce this value
+		for a smaller footprint.
+
+config LIBC_TZDIR
+	string "zoneinfo directory path"
+	default "/etc/zoneinfo"
+	---help---
+		This is the full path to the location where the TZ database is expected
+		to be found.
+
+config LIB_ZONEINFO
+	bool "TZ database"
+	default n
+	---help---
+		Download and build the TZ/Olson database.
+
+if LIB_ZONEINFO
+
+config LIB_ZONEINFO_ROMFS
+	bool "Build ROMFS filesystem"
+	default n
+	depends on FS_ROMFS
+	---help---
+		Build a mountable ROMFS filesystem containing the TZ/Olson database
+
+endif # LIB_ZONEINFO
+endif # LIBC_LOCALTIME
+
+config TIME_EXTENDED
+	bool "Add day of week, year support"
+	default "n"
+	depends on !LIBC_LOCALTIME
+	---help---
+		Selecting TIME_EXTENDED adds tm_wday, tm_yday and tm_isdst
+		to the tm struct. This allows integration with 3rd party libraries
+		that expect the tm struct to contain these members.
+
+		Note: tm_isdst is always 0
diff --git a/libc/tls/Kconfig b/libc/tls/Kconfig
new file mode 100644
index 0000000000..b036adbcda
--- /dev/null
+++ b/libc/tls/Kconfig
@@ -0,0 +1,51 @@
+#
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+config ARCH_HAVE_TLS
+	bool
+	default n
+	---help---
+		Selected by the configuration system if the current architecture
+		supports TLS.
+
+if ARCH_HAVE_TLS
+
+comment "Thread Local Storage"
+
+menuconfig TLS
+	bool "Thread Local Storage (TLS)"
+	default n
+	---help---
+		Build in support for stack based thread local storage (TLS).
+
+if TLS
+
+config TLS_LOG2_MAXSTACK
+	int "Maximum stack size (log2)"
+	default 13
+	range 11 24
+	---help---
+		Stack based TLS works by fetch thread information from the beginning
+		of the stack memory allocation.  In order to do this, the memory
+		must be aligned in such a way that the executing logic can simply
+		masking the current stack pointer to get the beginning of the stack
+		allocation.
+
+		This setting specifies the alignment of the stack as a power of 2:
+		11=2KB, 12=4KB, 13=8KB, etc.  The exact alignment is not so critical
+		except that (1) a very large value can cause you to run out of
+		alignable memory (and fail memory allocations), and (2) smaller
+		values will limit the maximum size of the stack (hence the naming
+		of this configuration value).
+
+config TLS_NELEM
+	int "Number of TLS elements"
+	default 1
+	---help---
+		The number of unique TLS elements.  These can be accessed with
+		the user library functions tls_get_element() and tls_set_element().
+
+endif # TLS
+endif # ARCH_HAVE_TLS
diff --git a/libc/unistd/Kconfig b/libc/unistd/Kconfig
new file mode 100644
index 0000000000..030e9cfb9d
--- /dev/null
+++ b/libc/unistd/Kconfig
@@ -0,0 +1,88 @@
+#
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+comment "Program Execution Options"
+
+config LIBC_EXECFUNCS
+	bool "Enable exec[l|v] / posix_spawn() Support"
+	default n
+	depends on !BINFMT_DISABLE
+	---help---
+		Enable support for the exec[l|v] family of functions that can be
+		used to start other programs, terminating the current program and
+		the posix_spawn() familty of functions that can be used start other
+		programs without terminating the current program.  The typical
+		usage of the exec[l|v] functions is (1) first call vfork() to create
+		a new thread, then (2) call exec[l|v] to replace the new thread with
+		a program from the file system.
+
+		NOTE 1: This two step process start is completely unnecessary in
+		NuttX and is provided only for compatibily with Unix systems.  These
+		functions are essentially just wrapper functions that (1) call the
+		non-standard binfmt function 'exec', and then (2) exit(0).  Since
+		the new thread will be terminated by the exec[l|v] call, it really
+		served no purpose other than to suport Unix compatility.
+
+		The posix_spawn() functions do not have this inefficiency.
+
+		NOTE 2: Support for exec[l|v] and posix_spawn() is conditional
+		because they require additional support for symbol tables that
+		will not be available in the typical system.
+
+if LIBC_EXECFUNCS
+
+config EXECFUNCS_HAVE_SYMTAB
+	bool "Have symbol table"
+	default n if BUILD_KERNEL
+	default y if !BUILD_KERNEL
+	---help---
+		If you have a system symbol table, then you must select this
+		option in order to use it.  Symbol tables are required in most
+		cases in order to like executable programs to the base code.
+
+if EXECFUNCS_HAVE_SYMTAB
+config EXECFUNCS_SYMTAB
+	string "Symbol table used by exec[l|v]"
+	default "g_symtab"
+	---help---
+		The exec[l|v] and posix_spawn() functions are wrapper functions that
+		call the non-standard binfmt function 'exec').  The binfmt
+		function 'exec' needs to have (1) a symbol table that provides the
+		list of symbols exported by the base code, and (2) the number of
+		symbols in that table.  This selection provides the name of that
+		symbol table.
+
+config EXECFUNCS_NSYMBOLS
+	int "Number of Symbols in the Table"
+	default 0
+	---help---
+		The exec[l|v] and posix_spawn() functions are wrapper functions that
+		call the non-standard binfmt function 'exec').  The binfmt
+		function 'exec' needs to have (1) a symbol table that provides the
+		list of symbols exported by the base code, and (2) the number of
+		symbols in that table.  This selection provides the number of
+		symbols in the symbol table.
+
+endif # EXECFUNCS_HAVE_SYMTAB
+endif # LIBC_EXECFUNCS
+
+config POSIX_SPAWN_PROXY_STACKSIZE
+	int "Spawn Stack Size"
+	default 1024
+	---help---
+		If posix_spawn[p]() and task_spawn() use I/O redirection options,
+		they will require an intermediary/proxy task to muck with the file
+		descriptors.  This configuration item specifies the stack size
+		used for the proxy. Default: 1024 bytes.
+
+config TASK_SPAWN_DEFAULT_STACKSIZE
+	int "Default task_spawn Stack Size"
+	default 2048
+	depends on !ARCH_ADDRENV
+	---help---
+		The actual size to use for the child task's stack can be set with
+		task_spawnattr_setstacksize().  This value specifies the default
+		stack size to use if task_spawnattr_setstacksize() is not used.
+		Default: 2048.
diff --git a/libc/wchar/Kconfig b/libc/wchar/Kconfig
new file mode 100644
index 0000000000..d65dbee449
--- /dev/null
+++ b/libc/wchar/Kconfig
@@ -0,0 +1,12 @@
+#
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+comment "Wide character suppoort"
+
+config LIBC_WCHAR
+	bool "Enable wide-characters (Unicode) support"
+	default n
+	---help---
+		By default, wide-characters support is disabled.
diff --git a/libc/wqueue/Kconfig b/libc/wqueue/Kconfig
new file mode 100644
index 0000000000..9d3b8a1474
--- /dev/null
+++ b/libc/wqueue/Kconfig
@@ -0,0 +1,40 @@
+#
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+if BUILD_PROTECTED || BUILD_KERNEL
+
+comment "User Work Queue Support"
+
+config LIB_USRWORK
+	bool "User mode worker thread"
+	default n
+	depends on !DISABLE_SIGNALS
+	---help---
+		User space work queues can also be made available for deferred
+		processing in the NuttX kernel build.
+
+if LIB_USRWORK
+
+config LIB_USRWORKPRIORITY
+	int "User mode priority worker thread priority"
+	default 100
+	---help---
+		The execution priority of the user-mode priority worker thread.  Default: 100
+
+config LIB_USRWORKPERIOD
+	int "User mode worker thread period"
+	default 100000
+	---help---
+		How often the lower priority worker thread checks for work in units
+		of microseconds. Default: 100*1000 (100 MS).
+
+config LIB_USRWORKSTACKSIZE
+	int "User mode worker thread stack size"
+	default 2048
+	---help---
+		The stack size allocated for the lower priority worker thread.  Default: 2K.
+
+endif # LIB_USRWORK
+endif # BUILD_PROTECTED || BUILD_KERNEL