mkmf.rb: ignore linker warnings
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62007 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
mkmf.rb: ignore linker warnings
unexpected failures on OpenBSD. [ruby-core:78827] [Bug #13069]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62007 b2dd03c8-39d4-4d8f-98ff-823fe69b080e