test/psych is executed without libyaml
|ruby -v:||ruby 1.9.2dev (2010-03-30 trunk 27106) [x86_64-darwin10.3.0]||Backport:|
When I make test-all at trunk, test/psych is executed even if the system
does not have libyaml. test/zlib and others aren't executed if building *.so fails.