diff --git a/make/rules.mk b/make/rules.mk
index ff33ff62..63266255 100644
--- a/make/rules.mk
+++ b/make/rules.mk
@@ -65,7 +65,7 @@ $(TOPDIR)/include:
 	mkdir -p $@
 
 $(TOPDIR)/include/%.h: %.h
-	mkdir -p $(dir $@); cp $(@F) $@
+	mkdir -p $(dir $@); cp $< $@
 
 $(TOPDIR)/bin/%.sh: %.sh
 	mkdir -p $(dir $@); install -m 755 $(@F) $@