diff --git a/Makefile b/Makefile
index ab23ad5..6968ae0 100644
--- a/Makefile
+++ b/Makefile
@@ -9,15 +9,19 @@ lib:
 
 .PHONY: exe
 exe:
-	make -C exe exe
+	$(MAKE) -C exe exe
 
 .PHONY: test
 test:
-	make -C tests test
+	$(MAKE) -C tests test
+
+.PHONY: prove
+prove:
+	$(MAKE) -C tests prove
 
 .PHONY: clean
 clean:
-	rm -rf build depends
-	rm -f quox
-	make -C exe clean
-	make -C tests clean
+	$(RM) -r build depends
+	$(RM) quox
+	$(MAKE) -C exe clean
+	$(MAKE) -C tests clean
diff --git a/exe/Makefile b/exe/Makefile
index 19b9fb3..287a38a 100644
--- a/exe/Makefile
+++ b/exe/Makefile
@@ -2,7 +2,7 @@ all: test
 
 .PHONY: lib
 lib:
-	make -C .. lib
+	$(MAKE) -C .. lib
 
 depends/quox: lib
 	mkdir -p depends
@@ -14,4 +14,4 @@ exe: depends/quox
 
 .PHONY: clean
 clean:
-	rm -rf build depends
+	$(RM) -r build depends
diff --git a/tests/Makefile b/tests/Makefile
index c757352..835ba35 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -2,7 +2,7 @@ all: test
 
 .PHONY: lib
 lib:
-	make -C .. lib
+	$(MAKE) -C .. lib
 
 depends/quox: lib
 	mkdir -p depends
@@ -23,4 +23,4 @@ prove: build-tests
 
 .PHONY: clean
 clean:
-	rm -rf build depends
+	$(RM) -r build depends