merge revision(s) 50717: [Backport #11201]
* lib/mkmf.rb (pkg_config): split --libs if --libs-only-l option is not available. patch in [ruby-core:69428] by Hans Mackowiak. [ruby-core:69421] [Bug #11201]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_1@51123 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
merge revision(s) 50717: [Backport #11201]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_1@51123 b2dd03c8-39d4-4d8f-98ff-823fe69b080e