--- /dev/null
+# This test is meant to confirm some basic redo functionality
+# related to static files not in the build tree. But if your
+# system doesn't happen to have stdio.h in the usual location,
+# let's not explode just for that.
+stdio=/usr/include/stdio.h
+[ -e "$stdio" ] || stdio=
+
+redo-ifchange CC hello.c $stdio
+redo-ifcreate stdio.h
+../sleep 3
+./CC hello.c