diff --git a/libobjc/ChangeLog b/libobjc/ChangeLog
index e800cbeffd1cf25ef9a3521f95d5e48492927216..34c3e8e8b0c27c2d0b81b4434768f4438def7fde 100644
--- a/libobjc/ChangeLog
+++ b/libobjc/ChangeLog
@@ -1,3 +1,8 @@
+2015-02-05  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
+
+	PR libobjc/63765
+	* thr.c (_XOPEN_SOURCE): Remove.
+
 2015-01-27  Matthias Klose  <doko@ubuntu.com>
 
 	* sendmsg.c: Add prototypes for __objc_get_forward_imp and get_imp.
diff --git a/libobjc/thr.c b/libobjc/thr.c
index f45a752afb38628cf672de6a375516e27722c6be..4b16d4b059c43d91dd473892b883e3cddba94469 100644
--- a/libobjc/thr.c
+++ b/libobjc/thr.c
@@ -25,11 +25,6 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #include "objc-private/common.h"
 #include "objc-private/error.h"
 #define _LIBOBJC
-/* The line below is needed for declarations of functions such as
-   pthread_mutexattr_settype, without which gthr-posix.h may fail to
-   compile within libobjc.  While we only need XPG5 for this, Solaris
-   requires XPG6 for C99 and later.  */
-#define _XOPEN_SOURCE 600
 #include "config.h"
 #include "tconfig.h"
 #include "coretypes.h"