* gc.c (rb_gc_force_recycle): we only need to know the result (0/1)
  of RVALUE_OLD_P(). clang fails to compile it because is_old is
  `int' but RVALUE_OLD_P() returns VALUE.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46332 b2dd03c8-39d4-4d8f-98ff-823fe69b080e