Fix configure check for PTHREAD_ONCE_INIT when manually adding -Wall to CFLAGS.

(closes issue #16666)
Reported by: romain_proformatique


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@241932 65c4cc65-6c06-0410-ace0-fbb531ad65f3

configure

@@ -1,5 +1,5 @@
 #! /bin/sh
-# From configure.ac Revision: 235652 .
+# From configure.ac Revision: 236585 .
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.64 for asterisk 1.4.
 #
@@ -11491,10 +11491,11 @@ CFLAGS="${CFLAGS} -Werror -Wmissing-braces"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 #include <pthread.h>
+     void empty(){}
 int
 main ()
 {
-pthread_once_t once = PTHREAD_ONCE_INIT;
+pthread_once_t once = PTHREAD_ONCE_INIT; pthread_once(&once, empty);
   ;
   return 0;
 }

configure.ac

@@ -357,8 +357,9 @@ saved_CFLAGS="${CFLAGS}"
 CFLAGS="${CFLAGS} -Werror -Wmissing-braces"
 AC_COMPILE_IFELSE(
   [AC_LANG_PROGRAM(
-    [#include <pthread.h>],
-	[pthread_once_t once = PTHREAD_ONCE_INIT;])
+    [#include <pthread.h>
+     void empty(){}],
+	[pthread_once_t once = PTHREAD_ONCE_INIT; pthread_once(&once, empty);])
   ],[
     AC_MSG_RESULT(no)
     ac_cv_pthread_once_needsbraces="no"