merge revision(s) 41734,41737: [Backport #8596]

	* 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/branches/ruby_2_0_0@41758 b2dd03c8-39d4-4d8f-98ff-823fe69b080e