include/nuttx/nx/nxmu.h: This header file coul be lethal; it declared an #error if CONFIG_DISABLE_MQUEUE=y.

TODO

@@ -789,12 +789,16 @@ o Signals (sched/signal, arch/)
                  actual signal action as well as some housekeeping functions
                  then 
                - up_sigdeliver() performs a context switch back to the normal,
-                 uninterrupted thread.
+                 uninterrupted thread instead of returning to nxsig_deliver().
 
                The loop in nxsig_deliver() then will have the opportunity to
                run until when that normal, uniterrupted thread is suspended.
                Then the loop will continue with the next queued signal
                action.
+
+               Normally signals execute immediately.  The is the whole reason
+               why almost all blocking APIs return when a signal is received
+               (with errno equal to EINTR).
   Status:      Open
   Priority:    Low.  This design flaw has been around for ages and no one has yet
                complained about it.  Apparently the visibility of the problem is

configs/boardctl.c

@@ -48,7 +48,10 @@
 #include <nuttx/board.h>
 #include <nuttx/lib/modlib.h>
 #include <nuttx/binfmt/symtab.h>
-#include <nuttx/nx/nxmu.h>
+
+#ifdef CONFIG_NX
+#  include <nuttx/nx/nxmu.h>
+#endif
 
 #ifdef CONFIG_BOARDCTL_USBDEVCTRL
 #  include <nuttx/usb/cdcacm.h>

include/nuttx/nx/nxmu.h

@@ -56,10 +56,6 @@
 
 /* Configuration ************************************************************/
 
-#ifdef CONFIG_DISABLE_MQUEUE
-#  error "Message queues are disabled(CONFIG_DISABLE_MQUEUE)"
-#endif
-
 #ifndef CONFIG_NX_MXSERVERMSGS
 #  define CONFIG_NX_MXSERVERMSGS 32 /* Number of pending messages in server MQ */
 #endif