diff --git a/stm/Makefile b/stm/Makefile
index c66a2f6ce6..33d738d78f 100644
--- a/stm/Makefile
+++ b/stm/Makefile
@@ -193,6 +193,6 @@ $(BUILD)/compile.o: $(PYSRC)/grammar.h
 $(BUILD)/emitbc.o: $(PYSRC)/emit.h
 
 clean:
-	/bin/rm -r $(BUILD)
+	/bin/rm -rf $(BUILD)
 
 .PHONY: all clean
diff --git a/unix-cpy/Makefile b/unix-cpy/Makefile
index a77a6308b1..ef1999a1b0 100644
--- a/unix-cpy/Makefile
+++ b/unix-cpy/Makefile
@@ -86,6 +86,6 @@ $(BUILD)/emitcpy.o: $(PYSRC)/emit.h
 $(BUILD)/emitbc.o: $(PYSRC)/emit.h
 
 clean:
-	/bin/rm -r $(BUILD)
+	/bin/rm -rf $(BUILD)
 
 .PHONY: clean
diff --git a/unix/Makefile b/unix/Makefile
index f6b91889bb..0ddf11539a 100644
--- a/unix/Makefile
+++ b/unix/Makefile
@@ -95,6 +95,6 @@ $(BUILD)/emitcpy.o: $(PYSRC)/emit.h
 $(BUILD)/emitbc.o: $(PYSRC)/emit.h
 
 clean:
-	/bin/rm -r $(BUILD)
+	/bin/rm -rf $(BUILD)
 
 .PHONY: clean