Use Command Prompt for stdlib test on Windows

Author: chyndman

Makefile

@@ -175,7 +175,11 @@ test_doc_test: compile
 test_stdlib: compile
 	@ echo "==> elixir (exunit)"
 	$(Q) exec epmd & exit
-	$(Q) cd lib/elixir && ../../bin/elixir -r "test/elixir/test_helper.exs" -pr "test/elixir/**/*_test.exs";
+	$(Q) if [ $(OS) = Windows_NT ]; then \
+		cd lib/elixir && cmd //C call ../../bin/elixir.bat -r "test/elixir/test_helper.exs" -pr "test/elixir/**/*_test.exs"; \
+	else \
+		cd lib/elixir && ../../bin/elixir -r "test/elixir/test_helper.exs" -pr "test/elixir/**/*_test.exs"; \
+	fi
 
 #==> Dialyzer tasks