ext_conf_builder.rb: hack for obsolete sytle gems
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39560 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
ext_conf_builder.rb: hack for obsolete sytle gems
(Gem::Ext::ExtConfBuilder.hack_for_obsolete_sytle_gems): remove
circular dependencies for old style gems which locate extconf.rb on
the toplevel. [ruby-core:53059] [ruby-trunk - Bug #7698]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39560 b2dd03c8-39d4-4d8f-98ff-823fe69b080e