o src/sys/capability.h provides a number of support macros that are not

documented by POSIX.1e, and understand the opaque capability structures.
  Introduce support in the userland POSIX.1e library for a
  _CAPABILITY_NEEDMACROS define to remove these macros from the normal
  namespace, but allow the libc functions to use them.

Submitted by:	tmm
Obtained from:	TrustedBSD Project

lib/libc/posix1e/cap_get_flag.c

@@ -31,7 +31,9 @@
 
 #include <sys/types.h>
 #include "namespace.h"
+#define _CAPABILITY_NEEDMACROS
 #include <sys/capability.h>
+#undef _CAPABILITY_NEEDMACROS
 #include "un-namespace.h"
 #include <sys/errno.h>
 

lib/libc/posix1e/cap_set_flag.c

@@ -31,7 +31,10 @@
 
 #include <sys/types.h>
 #include "namespace.h"
+/* need capability.h macros */
+#define _CAPABILITY_NEEDMACROS
 #include <sys/capability.h>
+#undef _CAPABILITY_NEEDMACROS
 #include "un-namespace.h"
 #include <sys/errno.h>