Ruby » Ruby master

mkmf.rb: fix r36815

• lib/mkmf.rb (create_makefile): remove unnecessary rule and newline.
  [ruby-dev:46067] [Bug #6904]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@36818 b2dd03c8-39d4-4d8f-98ff-823fe69b080e