diff --git a/make/topdir.mk b/make/topdir.mk
index 7353cf37..28a63504 100644
--- a/make/topdir.mk
+++ b/make/topdir.mk
@@ -34,8 +34,12 @@ unlocal:
 	rm -f $(shell find . -name local.mk)
 
 topdir.distclean:
-
 topdir.clean:
+	rm -r *.done
 
-topdir.install: $(INSTALLED_TOPDIR_FILES)
+topdir.install: prefix.done $(INSTALLED_TOPDIR_FILES)
+
+prefix.done:
+	mkdir -p $(PREFIX)
+	touch $@