internal.h: export rb_gc_for_fd
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52730 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
internal.h: export rb_gc_for_fd
ext/socket.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52730 b2dd03c8-39d4-4d8f-98ff-823fe69b080e