Deprecate inclusion of <sys/sysmacros.h> by <sys/types.h>

The macros defined by <sys/sysmacros.h> are not part of POSIX nor XSI, and
their names frequently collide with user code; see for instance glibc bug
19239 and Red Hat bug 130601.  <stdlib.h> includes <sys/types.h> under
_GNU_SOURCE, and C++ code presently cannot avoid being compiled under
_GNU_SOURCE, exacerbating the problem.

	* NEWS: Inclusion of <sys/sysmacros.h> by <sys/types.h> is deprecated.
	* misc/sys/sysmacros.h: If __SYSMACROS_DEPRECATED_INCLUSION is defined,
	define major, minor, and makedev to issue deprecation warnings on use.
	If __SYSMACROS_DEPRECATED_INCLUSION is *not* defined, suppress
	previously-activated deprecation warnings for these macros and prevent
	subsequent inclusions of this header from having any effect.
	* posix/sys/types.h: Define __SYSMACROS_DEPRECATED_INCLUSION before
	including <sys/sysmacros.h>, and undefine it again afterward.

1 files changed, 10 insertions, 0 deletions

diff --git a/NEWS b/NEWS
index 495bde01be..25c771df2e 100644
--- a/NEWS
+++ b/NEWS
@@ -17,6 +17,16 @@ Version 2.25
   from that TS.  Note that most features from that TS are not supported by
   the GNU C Library.
 
+* The inclusion of <sys/sysmacros.h> by <sys/types.h> is deprecated.  This
+  means that in a future release, the macros “major”, “minor”, and “makedev”
+  will only be available from <sys/sysmacros.h>.
+
+  These macros are not part of POSIX nor XSI, and their names frequently
+  collide with user code; see for instance glibc bug 19239 and Red Hat bug
+  130601.  <stdlib.h> includes <sys/types.h> under _GNU_SOURCE, and C++ code
+  presently cannot avoid being compiled under _GNU_SOURCE, exacerbating the
+  problem.
+
 Security related changes:
 
   [Add security related changes here]