Don't redefine _THREAD_SAFE (bug #2332)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@3688 65c4cc65-6c06-0410-ace0-fbb531ad65f3

stdtime/localtime.c

@@ -21,7 +21,9 @@
  *
  * Don't mess with these unless you're really sure you know what you're doing.
  */
+#ifndef _THREAD_SAFE
 #define _THREAD_SAFE
+#endif
 #define TZ_STRLEN_MAX	255
 /* #define DEBUG */
 #include <asterisk/lock.h>