Adjust in response to various bits of brucification:

1) Fix style issues in comments.
2) Properly namespaceify changes
3) Appropriate sectioning of changes

Not changed: parenthesis around macro rvalue.  That would make the additions
inconsistent with the other entries there, merely a different style violation
rather than a clear and obvious improvement so I'm going to have to disagree
with the judges on that one.  If someone wishes to adjust *all* the rvalues
to conform to fully parenthesized marco rule, that would be both consistent
and reasonable but that's beyond the scope of the changes I wish to make at
this time.

include/fnmatch.h

@@ -45,7 +45,9 @@
 #define	FNM_PATHNAME	0x02	/* Slash must be matched by slash. */
 #define	FNM_PERIOD	0x04	/* Period must be matched by period. */
 
-#define FNM_NOSYS	-1	/* Reserved */
+#if __XSI_VISIBLE
+#define	FNM_NOSYS	-1	/* Reserved. */
+#endif
 
 #if __BSD_VISIBLE
 #define	FNM_LEADING_DIR	0x08	/* Ignore /<tail> after Imatch. */

include/regex.h

@@ -75,7 +75,7 @@ typedef struct {
 #define	REG_DUMP	0200
 
 /* regerror() flags */
-#define	REG_ENOSYS	-1	/* Reserved */
+#define	REG_ENOSYS	-1
 #define	REG_NOMATCH	 1
 #define	REG_BADPAT	 2
 #define	REG_ECOLLATE	 3