[PATCH v2] fnmatch.h: use standard internal defines

[Mike Frysinger <vapier@gentoo.org>]

Use features.h for the start/end brackets of C code, and switch to
using __USE_GNU/__USE_XOPEN/__USE_XOPEN2K8 rather than parsing the
symbols directly.

We also drop support for exporting the GNU-extensions when
_POSIX_C_SOURCE is defined to 1 as these aren't in POSIX.

2016-11-27  Mike Frysinger  <vapier@gentoo.org>

	* posix/fnmatch.h: Include features.h.  Replace extern "C" with
	__BEGIN_DECLS and __END_DECLS.  Drop _POSIX_C_SOURCE checking.
	Change _GNU_SOURCE to __USE_GNU.  Change _XOPEN_SOURCE to
	__USE_XOPEN && !__USE_XOPEN2K8.
---
v2
	- add __USE_XOPEN2K8 checking

 posix/fnmatch.h | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/posix/fnmatch.h b/posix/fnmatch.h
index 71991617abe5..55031f5b3042 100644
--- a/posix/fnmatch.h
+++ b/posix/fnmatch.h
@@ -18,9 +18,9 @@
 #ifndef	_FNMATCH_H
 #define	_FNMATCH_H	1
 
-#ifdef	__cplusplus
-extern "C" {
-#endif
+#include <features.h>
+
+__BEGIN_DECLS
 
 /* We #undef these before defining them because some losing systems
    (HP-UX A.08.07 for example) define these in <unistd.h>.  */
@@ -33,7 +33,7 @@ extern "C" {
 #define	FNM_NOESCAPE	(1 << 1) /* Backslashes don't quote special chars.  */
 #define	FNM_PERIOD	(1 << 2) /* Leading `.' is matched only explicitly.  */
 
-#if !defined _POSIX_C_SOURCE || _POSIX_C_SOURCE < 2 || defined _GNU_SOURCE
+#ifdef __USE_GNU
 # define FNM_FILE_NAME	 FNM_PATHNAME	/* Preferred GNU name.  */
 # define FNM_LEADING_DIR (1 << 3)	/* Ignore `/...' after a match.  */
 # define FNM_CASEFOLD	 (1 << 4)	/* Compare without regard to case.  */
@@ -47,7 +47,7 @@ extern "C" {
    `fnmatch'.  Since this is not the case here it will never be
    returned but the conformance test suites still require the symbol
    to be defined.  */
-#ifdef _XOPEN_SOURCE
+#if defined __USE_XOPEN && !defined __USE_XOPEN2K8
 # define FNM_NOSYS	(-1)
 #endif
 
@@ -55,8 +55,6 @@ extern "C" {
    returning zero if it matches, FNM_NOMATCH if not.  */
 extern int fnmatch (const char *__pattern, const char *__name, int __flags);
 
-#ifdef	__cplusplus
-}
-#endif
+__END_DECLS
 
 #endif /* fnmatch.h */
-- 
2.12.0