* include/ruby/ruby.h: enable RGENGC (USE_RGENGC)
  but no type creates write protected (sunny) objects
  (RGENGC_WB_PROTECTED_* == 0).



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40704 b2dd03c8-39d4-4d8f-98ff-823fe69b080e