Index: mono-3.10.0/mcs/class/Managed.Windows.Forms/Makefile
===================================================================
--- mono-3.10.0.orig/mcs/class/Managed.Windows.Forms/Makefile
+++ mono-3.10.0/mcs/class/Managed.Windows.Forms/Makefile
@@ -122,11 +122,11 @@ TEST_HARNESS_EXCLUDES_ONDOTNET = -exclud
 $(the_lib): $(RESOURCES)
 
 $(RESX_RESOURCES): %.resources: %.resx
-	$(RESGEN) $< || cp $@.prebuilt $@
+	$(RESGEN) $< || cp -r $@.prebuilt $@
 
 $(LIBRARY): $(CUR_RESOURCES)
 
 $(PREBUILT): %.prebuilt: %
-	cp $* $@
+	cp -r $* $@
 
 dist-default: $(PREBUILT)