Clean up some spacing in the last commit... Seemed like a good idea at the time, but it is better to be consisten than better.

include/unistd.h

@@ -1,7 +1,8 @@
 /****************************************************************************
  * include/unistd.h
  *
- *   Copyright (C) 2007-2009, 2013-2014, 2016-2018 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2009, 2013-2014, 2016-2018 Gregory Nutt. All rights
+ *     reserved.
  *   Author:  Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -108,8 +109,8 @@
 #undef  _POSIX_ASYNC_IO
 #undef  _POSIX_PRIO_IO
 
-/* Constants used with POSIX sysconf().
- * Most of these will return -1 and ENOSYS
+/* Constants used with POSIX sysconf().  sysconf() will return -2 and set
+ * errno to ENOSYS for most of these.
  */
 
 #define _SC_2_C_BIND                     0x0001
@@ -244,7 +245,7 @@
 
 #define HOST_NAME_MAX                    32
 
-/* Helpers and compatibility definitions */
+/* Helpers and legacy compatibility definitions */
 
 #define fdatasync(f)                     fsync(f)
 #define getdtablesize(f)                 ((int)sysconf(_SC_OPEN_MAX))
@@ -356,8 +357,8 @@ int     getopt(int argc, FAR char *const argv[], FAR const char *optstring);
  */
 
 FAR char **getoptargp(void);  /* Optional argument following option */
-int       *getoptindp(void); /* Index into argv */
-int       *getoptoptp(void); /* Unrecognized option character */
+FAR int   *getoptindp(void);  /* Index into argv */
+FAR int   *getoptoptp(void);  /* Unrecognized option character */
 
 #ifdef CONFIG_NET
 int     gethostname(FAR char *name, size_t size);

libc/unistd/lib_sysconf.c

@@ -226,7 +226,11 @@ long sysconf(int name)
         return CONFIG_NFILE_DESCRIPTORS;
 
       default:
+#if 0 /* Assume valid but not implemented for the time being */
         errcode = EINVAL;
+#else
+        errcode = ENOSYS;
+#endif
         break;
     }