Don't allow tagging a dirty repo.

Author: xach

Makefile

@@ -6,6 +6,5 @@ clean:
 	rm -f quicklisp.tar quicklisp.tar.gz
 
 tag:
+	test -z "`git status -s quicklisp/ asdf.lisp setup.lisp`"
 	git tag version-`cat quicklisp/version.txt`
-
-