move AC_GNU_SOURCE higher up as required

configure.in

@@ -21,6 +21,9 @@
 AC_INIT(src/flac/main.c)
 AM_INIT_AUTOMAKE(flac, 1.1.1)
 
+dnl In order to have access to any available wcsdup() and wcscasecmp()
+AC_GNU_SOURCE
+
 # Don't automagically regenerate autoconf/automake generated files unless
 # explicitly requested.  Eases autobuilding -mdz
 AM_MAINTAINER_MODE
@@ -36,9 +39,6 @@ AM_PROG_AS
 AC_PROG_CXX
 AC_PROG_MAKE_SET
 
-dnl In order to have access to any available wcsdup() and wcscasecmp()
-AC_GNU_SOURCE
-
 dnl check for getopt in standard library
 dnl AC_CHECK_FUNCS(getopt_long , , [LIBOBJS="$LIBOBJS getopt.o getopt1.o"] )
 AC_CHECK_FUNCS(getopt_long, [], [])