missing header.

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@5113 d0543943-73ff-0310-b7d9-9358b9ac24b2

libs/sofia-sip/libsofia-sip-ua/stun/stun.c

@@ -39,6 +39,7 @@
 
 #include <assert.h>
 #include <string.h>
+#include <time.h>
 
 #define SU_ROOT_MAGIC_T struct stun_magic_t