Clean up autoconf file (gets rid of warnings seen when rebuilding configure) and rebuild configure.

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@48960 65c4cc65-6c06-0410-ace0-fbb531ad65f3

configure.ac

@@ -21,6 +21,9 @@ AC_CONFIG_HEADER(include/asterisk/autoconfig.h)
 AC_COPYRIGHT("Asterisk")
 AC_REVISION($Revision$)
 
+AC_GNU_SOURCE
+AC_USE_SYSTEM_EXTENSIONS
+
 case "${host_os}" in
      freebsd*)
      ac_default_prefix=/usr/local
@@ -89,9 +92,6 @@ if test ! x"${UNAME}" = xNo; then
 fi
 AC_SUBST(PBX_OSREV)
 
-# This needs to be before any macros that use the C compiler
-AC_GNU_SOURCE
-
 AH_TOP(
 #ifndef ASTERISK_AUTOCONFIG_H
 #define ASTERISK_AUTOCONFIG_H