mkmf.rb: untabify

* lib/mkmf.rb: untabify.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@37003 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/mkmf.rb

@@ -1,4 +1,3 @@
-# -*- indent-tabs-mode: t -*-
 # module to create Makefile for extension modules
 # invoke like: ruby -r mkmf extconf.rb