diff -r 000000000000 -r 6474c204b198 build/pymake/tests/unexport.submk
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/build/pymake/tests/unexport.submk	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,15 @@
+# -@- Mode: Makefile -@- 
+
+unexport VAR1
+
+all:
+	env
+	test "$(VAR1)" = "val1"
+	test "$(origin VAR1)" = "environment"
+	test "$(VAR2)" = "" # VAR2
+	test "$(VAR3)" = "val3"
+	test "$(ENVVAR)" = ""
+	$(MAKE) -f $(TESTPATH)/unexport.submk subt
+
+subt:
+	test "$(VAR1)" = ""