configure.ac: Switch from _GCC_TOPLEV_NONCANONICAL_TARGET to ACX_NONCANONICAL_TARGET.

	* configure.ac: Switch from _GCC_TOPLEV_NONCANONICAL_TARGET to
	ACX_NONCANONICAL_TARGET.
	* configure: Regenerate.

From-SVN: r86690
diff --git a/libobjc/configure.ac b/libobjc/configure.ac
index a276d6e..b3c12ce 100644
--- a/libobjc/configure.ac
+++ b/libobjc/configure.ac
@@ -105,8 +105,7 @@
 AC_SUBST(toplevel_srcdir)
 
 AC_CANONICAL_SYSTEM
-_GCC_TOPLEV_NONCANONICAL_TARGET
-AC_SUBST(target_noncanonical)
+ACX_NONCANONICAL_TARGET
 
 # Export source directory.
 # These need to be absolute paths, yet at the same time need to