add abspath.mk and realpath.mk
diff --git a/test/abspath.mk b/test/abspath.mk
new file mode 100644
index 0000000..f0f598d
--- /dev/null
+++ b/test/abspath.mk
@@ -0,0 +1,5 @@
+# TODO
+foo = $(abspath ./foo)
+
+test:
+	echo $(foo)