futex_bits.h: Include errno.h.

	* config/linux/futex_bits.h: Include errno.h.
	(sys_futex0): If syscall returns -1, return -errno rather than
	-1.

From-SVN: r208855

libitm/ChangeLog

+2014-03-26  Jakub Jelinek  <jakub@redhat.com>
+
+	* config/linux/futex_bits.h: Include errno.h.
+	(sys_futex0): If syscall returns -1, return -errno rather than
+	-1.
+
 2014-03-26  Joseph Myers  <joseph@codesourcery.com>
 
 	* libitm.texi (Index): Rename to Library Index.

libitm/config/linux/futex_bits.h

@@ -31,9 +31,13 @@
 
 #include <unistd.h>
 #include <sys/syscall.h>
+#include <errno.h>
 
 static inline long
 sys_futex0 (std::atomic<int> *addr, long op, long val)
 {
-  return syscall (SYS_futex, (int*) addr, op, val, 0);
+  long res = syscall (SYS_futex, (int*) addr, op, val, 0);
+  if (__builtin_expect (res == -1, 0))
+    return -errno;
+  return res;
 }