* lib/mkmf.rb (try_config): Fix to not replace $LDFLAGS with $libs
          (1.9.3 behavior) [ruby-core:55752] [Bug #8595]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41734 b2dd03c8-39d4-4d8f-98ff-823fe69b080e