Fix limits.h NL_NMAX namespace (bug 19929).

bits/xopen_lim.h (included by limits.h if __USE_XOPEN) defines
NL_NMAX, but this constant was removed in the 2008 edition of POSIX so
should not be defined in that case.  This patch duly disables that
define for __USE_XOPEN2K8.  It remains enabled for __USE_GNU to avoid
affecting sysconf (_SC_NL_NMAX), the implementation of which uses
"#ifdef NL_NMAX".

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

	[BZ #19929]
	* include/bits/xopen_lim.h (NL_NMAX): Do not define if
	[__USE_XOPEN2K8 && !__USE_GNU].
	* conform/Makefile (test-xfail-XOPEN2K8/limits.h/conform): Remove
	variable.

ChangeLog

@@ -1,5 +1,11 @@
 2016-04-08  Joseph Myers  <joseph@codesourcery.com>
 
+	[BZ #19929]
+	* include/bits/xopen_lim.h (NL_NMAX): Do not define if
+	[__USE_XOPEN2K8 && !__USE_GNU].
+	* conform/Makefile (test-xfail-XOPEN2K8/limits.h/conform): Remove
+	variable.
+
 	[BZ #19925]
 	* sysdeps/unix/sysv/linux/alpha/bits/termios.h (XCASE): Do not
 	define if [!__USE_MISC && __USE_XOPEN2K].

conform/Makefile

@@ -225,7 +225,6 @@ test-xfail-POSIX2008/netinet/in.h/conform = yes
 test-xfail-POSIX2008/signal.h/conform = yes
 test-xfail-POSIX2008/sys/socket.h/conform = yes
 test-xfail-POSIX2008/sys/wait.h/conform = yes
-test-xfail-XOPEN2K8/limits.h/conform = yes
 test-xfail-XOPEN2K8/signal.h/conform = yes
 test-xfail-XOPEN2K8/stdio.h/conform = yes
 test-xfail-XOPEN2K8/sys/wait.h/conform = yes

include/bits/xopen_lim.h

@@ -77,7 +77,9 @@
 
 /* Maximum number of bytes in N-to-1 collation mapping.  We have no
    limit.  */
-#define NL_NMAX		INT_MAX
+#if defined __USE_GNU || !defined __USE_XOPEN2K8
+# define NL_NMAX	INT_MAX
+#endif
 
 /* Maximum set number.  We have no limit.  */
 #define NL_SETMAX	INT_MAX