Fix toplevel 'config.status --recheck' for --enable-lto.

/:
	* configure.ac: Add 'lto' to enable_languages, not
	new_enable_languages, and only if not already present.
	* configure: Regenerate.

configure

@@ -6593,7 +6593,10 @@ if test -d ${srcdir}/gcc; then
   # If LTO is enabled, add the LTO front end.
   extra_host_libiberty_configure_flags=
   if test "$enable_lto" = "yes" ; then
-    new_enable_languages="${new_enable_languages}lto,"
+    case ,${enable_languages}, in
+      *,lto,*) ;;
+      *) enable_languages="${enable_languages},lto" ;;
+    esac
     if test "${ENABLE_GOLD}" = "yes" ; then
       configdirs="$configdirs lto-plugin"
       extra_host_libiberty_configure_flags=--enable-shared