setup.mak: make Makefile stable
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60985 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
setup.mak: make Makefile stable
definition to make Makefile stable when they have been defaulted.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60985 b2dd03c8-39d4-4d8f-98ff-823fe69b080e