Fix sys/time.h timespec namespace (bug 20041)

[Joseph Myers]

For UNIX98 and older standards, sys/time.h should not define struct
timespec, but does so via the inclusion of sys/select.h (which is a
new header in the 2001 edition of POSIX, and defines struct timespec
because of the declaration of pselect, a new function in the 2001
edition of POSIX).  In turn, this affects some other headers that
themselves include sys/time.h.

This patch fixes this by conditioning the __need_timespec definition
in sys/select.h on __USE_XOPEN2K, the same condition used there for
the declaration of pselect (this has no effect on direct uses of
sys/select.h with feature test macros for any standard that includes
that header, since such standards result in __USE_XOPEN2K being
defined).

Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by the patch).

2016-05-03  Joseph Myers  <joseph@codesourcery.com>

	{BZ #20041]
	* misc/sys/select.h (__need_timespec): Only define if
	[__USE_XOPEN2K].
	* conform/Makefile (test-xfail-XPG4/sys/time.h/conform): Remove
	variable.
	(test-xfail-XPG4/utmpx.h/conform): Likewise.
	(test-xfail-UNIX98/sys/time.h/conform): Likewise.
	(test-xfail-UNIX98/utmpx.h/conform): Likewise.

diff --git a/conform/Makefile b/conform/Makefile
index 55cada5..d5273c1 100644
--- a/conform/Makefile
+++ b/conform/Makefile
@@ -184,24 +184,20 @@ test-xfail-XPG4/netinet/in.h/conform = yes
 test-xfail-XPG4/signal.h/conform = yes
 test-xfail-XPG4/stdlib.h/conform = yes
 test-xfail-XPG4/sys/stat.h/conform = yes
-test-xfail-XPG4/sys/time.h/conform = yes
 test-xfail-XPG4/sys/types.h/conform = yes
 test-xfail-XPG4/sys/wait.h/conform = yes
 test-xfail-XPG4/termios.h/conform = yes
 test-xfail-XPG4/ucontext.h/conform = yes
 test-xfail-XPG4/unistd.h/conform = yes
-test-xfail-XPG4/utmpx.h/conform = yes
 test-xfail-POSIX/sys/wait.h/conform = yes
 test-xfail-UNIX98/arpa/inet.h/conform = yes
 test-xfail-UNIX98/netdb.h/conform = yes
 test-xfail-UNIX98/netinet/in.h/conform = yes
 test-xfail-UNIX98/signal.h/conform = yes
 test-xfail-UNIX98/stdlib.h/conform = yes
-test-xfail-UNIX98/sys/time.h/conform = yes
 test-xfail-UNIX98/sys/wait.h/conform = yes
 test-xfail-UNIX98/ucontext.h/conform = yes
 test-xfail-UNIX98/unistd.h/conform = yes
-test-xfail-UNIX98/utmpx.h/conform = yes
 test-xfail-XOPEN2K/semaphore.h/conform = yes
 test-xfail-XOPEN2K/signal.h/conform = yes
 test-xfail-XOPEN2K/sys/wait.h/conform = yes
diff --git a/misc/sys/select.h b/misc/sys/select.h
index b852dac..52dd94f 100644
--- a/misc/sys/select.h
+++ b/misc/sys/select.h
@@ -39,7 +39,9 @@ typedef __sigset_t sigset_t;
 
 /* Get definition of timer specification structures.  */
 #define __need_time_t
-#define __need_timespec
+#ifdef __USE_XOPEN2K
+# define __need_timespec
+#endif
 #include <time.h>
 #define __need_timeval
 #include <bits/time.h>

-- 
Joseph S. Myers
joseph@codesourcery.com