--- rep-gtk-0.18.4/Makefile.in
+++ rep-gtk-0.18.4/Makefile.in
@@ -51,7 +51,7 @@
 	$(rep_DL_LD) $(CPPFLAGS) $(CFLAGS) -o $@ $^ $(LDFLAGS) $(REP_GTK_LIBS)
 
 %-glue.c : %.defs build-gtk.jlc
-	rep build-gtk.jlc -f build-gtk-batch $< $@
+	LC_ALL=C rep build-gtk.jlc -f build-gtk-batch $< $@
 
 build-gtk.jlc : build-gtk.jl
 	rep compiler -f compile-batch $<