Define TSVTX in tar.h for older POSIX (bug 16978).

As noted in bug 16978, older POSIX versions include

in the specified contents of <tar.h>, with only the 2001 edition
introducing the notion of XSI-conditional definitions and conditioning
that definition.  Thus, this macro should be defined for
!__USE_XOPEN2K as well as for __USE_XOPEN, and this patch duly defines
it in that case.  Tested x86_64.

	[BZ #16978]
	* posix/tar.h [!__USE_XOPEN2K] (TSVTX): Define macro.
	* conform/Makefile (test-xfail-POSIX/tar.h/conform): Remove
	variable.

ChangeLog

@@ -1,3 +1,10 @@
+2014-05-23  Joseph Myers  <joseph@codesourcery.com>
+
+	[BZ #16978]
+	* posix/tar.h [!__USE_XOPEN2K] (TSVTX): Define macro.
+	* conform/Makefile (test-xfail-POSIX/tar.h/conform): Remove
+	variable.
+
 2014-05-23  Richard Henderson  <rth@twiddle.net>
 
 	* sysdeps/unix/sysv/linux/alpha/nptl/Makefile: Merge into...

NEWS

@@ -18,7 +18,7 @@ Version 2.20
   16760, 16770, 16786, 16789, 16791, 16799, 16800, 16815, 16823, 16824,
   16831, 16838, 16849, 16854, 16876, 16877, 16885, 16888, 16890, 16912,
   16915, 16916, 16917, 16922, 16927, 16928, 16932, 16943, 16958, 16966,
-  16967, 16965, 16977.
+  16967, 16965, 16977, 16978.
 
 * The minimum Linux kernel version that this version of the GNU C Library
   can be used with is 2.6.32.

conform/Makefile

@@ -188,7 +188,6 @@ 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/tar.h/conform = yes
 test-xfail-UNIX98/arpa/inet.h/conform = yes
 test-xfail-UNIX98/fcntl.h/conform = yes
 test-xfail-UNIX98/langinfo.h/conform = yes

posix/tar.h

@@ -73,7 +73,7 @@
 /* The bits in mode: */
 #define TSUID	04000
 #define TSGID	02000
-#ifdef __USE_XOPEN
+#if defined __USE_XOPEN || !defined __USE_XOPEN2K
 # define TSVTX	01000
 #endif
 #define TUREAD	00400