attribute: new module

This simplifies use of GCC and C2X attributes like ‘deprecated’.
* MODULES.html.sh: Add attribute.
* doc/attribute.texi, lib/attribute.h, modules/attribute: New files.
* doc/gnulib.texi (Particular Modules): Add Attributes.
* lib/backupfile.c, lib/fnmatch.c, lib/freopen-safer.c:
* lib/mbrtoc32.c, lib/mbrtowc.c, lib/nstrftime.c, lib/quotearg.c:
* lib/savewd.c, lib/unistr/u8-uctomb-aux.c, lib/unistr/u8-uctomb.c:
* lib/vasnprintf.c:
Include attribute.h, and let it define FALLTHROUGH.
* lib/bitset/base.h, lib/c-stack.c (__attribute__): Remove macro.
* lib/bitset/base.h (ATTRIBUTE_UNUSED): Define in terms of
_GL_ATTRIBUTE_MAYBE_UNUSED, for forwards compatibility to C2X.
* lib/dfa.c (FALLTHROUGH): Define consistently with gl_COMMON_BODY.
This is a copy since Gawk doesn’t use Gnulib.
* lib/di-set.h (_GL_ATTRIBUTE_NONNULL): Remove definition that
is incompatible with gl_COMMON_BODY’s.  All uses changed.
* lib/fts.c: Include attribte.h, for FALLTHROUGH.
Keep the existing FALLTHROUGH definition since Glibc might use it,
and it does no harm to Gnulib’s FALLTHROUGH.
* lib/fts_.h, lib/inttostr.h:
(__GNUC_PREREQ): Remove; no longer needed.
(__attribute_warn_unused_result__): Remove.  All uses
replaced by _GL_ATTRIBUTE_NODISCARD.
* lib/gl_list.h, lib/gl_map.h, lib/gl_omap.h, lib/gl_oset.h:
* lib/gl_set.h: Prefer _GL_ATTRIBUTE_NODISCARD to an ifdeffed
__attribute__ ((__warn_unused_result__)), for forward
compatibility to C2X.
* lib/hash.h (_GL_ATTRIBUTE_WUR): Remove.  All uses replaced by
_GL_ATTRIBUTE_NODISCARD.
(_GL_ATTRIBUTE_DEPRECATED): Remove, since gl_COMMON_BODY defines it.
* lib/ino-map.h (_GL_ATTRIBUTE_NONNULL): Remove.  All uses
replaced by gl_COMMON_BODY’s implementation, which has a
slightly different signature.
* lib/safe-alloc.h (_GL_ATTRIBUTE_RETURN_CHECK):
Remove.  All uses replaced by _GL_ATTRIBUTE_NODISCARD.
* lib/unused-parameter.h (_GL_UNUSED_PARAMETER):
Define in terms of _GL_ATTRIBUTE_MAYBE_UNUSED.
No doubt all uses should be replaced, at some point.
* m4/gnulib-common.m4 (_GL_GNUC_PREREQ): New macro.
(_Noreturn): Use it.
(_GL_HAS_ATTRIBUTE, _GL_ATTRIBUTE_ALLOC_SIZE)
(_GL_ATTRIBUTE_ALWAYS_INLINE, _GL_ATTRIBUTE_ARTIFICIAL)
(_GL_ATTRIBUTE_COLD)
(_GL_ATTRIBUTE_DEPRECATED, _GL_ATTRIBUTE_ERROR)
(_GL_ATTRIBUTE_WARNING, _GL_ATTRIBUTE_EXTERNALLY_VISIBLE)
(_GL_ATTRIBUTE_FALLTHROUGH, _GL_ATTRIBUTE_FORMAT)
(_GL_ATTRIBUTE_LEAF, _GL_ATTRIBUTE_MAY_ALIAS)
(_GL_ATTRIBUTE_MAYBE_UNUSED)
(_GL_ATTRIBUTE_NODISCARD, _GL_ATTRIBUTE_NOINLINE)
(_GL_ATTRIBUTE_NONNULL, _GL_ATTRIBUTE_NONSTRING)
(_GL_ATTRIBUTE_NOTHROW, _GL_ATTRIBUTE_PACKED, _GL_ATTRIBUTE_PURE)
(_GL_ATTRIBUTE_SENTINEL): New macros.
* modules/backup-rename, modules/backupfile, modules/c-vasnprintf:
* modules/fnmatch, modules/freopen-safer, modules/fts:
* modules/mbrtoc32, modules/mbrtowc, modules/nstrftime:
* modules/quotearg, modules/savewd:
* modules/unistdio/u16-u16-vasnprintf:
* modules/unistdio/u16-vasnprintf:
* modules/unistdio/u32-u32-vasnprintf:
* modules/unistdio/u32-vasnprintf:
* modules/unistdio/u8-u8-vasnprintf:
* modules/unistdio/u8-vasnprintf:
* modules/unistdio/ulc-vasnprintf:
* modules/unistr/u8-uctomb, modules/vasnprintf:
(Depends-on:): Add attribute module.

1 files changed, 4 insertions, 21 deletions

diff --git a/lib/fts_.h b/lib/fts_.h
index 15c248cba8..e7a9ead770 100644
--- a/lib/fts_.h
+++ b/lib/fts_.h
@@ -249,30 +249,13 @@ typedef struct _ftsent {
         char fts_name[__FLEXIBLE_ARRAY_MEMBER]; /* file name */
 } FTSENT;
 
-#ifndef __GNUC_PREREQ
-# if defined __GNUC__ && defined __GNUC_MINOR__
-#  define __GNUC_PREREQ(maj, min) \
-         ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
-# else
-#  define __GNUC_PREREQ(maj, min) 0
-# endif
-#endif
-
-#if __GNUC_PREREQ (3,4)
-# undef __attribute_warn_unused_result__
-# define __attribute_warn_unused_result__ \
-   __attribute__ ((__warn_unused_result__))
-#else
-# define __attribute_warn_unused_result__ /* empty */
-#endif
-
 __BEGIN_DECLS
-FTSENT  *fts_children (FTS *, int) __THROW __attribute_warn_unused_result__;
-int      fts_close (FTS *) __THROW __attribute_warn_unused_result__;
+FTSENT  *fts_children (FTS *, int) __THROW _GL_ATTRIBUTE_NODISCARD;
+int      fts_close (FTS *) __THROW _GL_ATTRIBUTE_NODISCARD;
 FTS     *fts_open (char * const *, int,
                    int (*)(const FTSENT **, const FTSENT **))
-  __THROW __attribute_warn_unused_result__;
-FTSENT  *fts_read (FTS *) __THROW __attribute_warn_unused_result__;
+  __THROW _GL_ATTRIBUTE_NODISCARD;
+FTSENT  *fts_read (FTS *) __THROW _GL_ATTRIBUTE_NODISCARD;
 int      fts_set (FTS *, FTSENT *, int) __THROW;
 __END_DECLS