* gc.c (ruby_gc_set_params): if RUBY_GC_OLDMALLOC_LIMIT is provided,
  then set objspace->rgengc.oldmalloc_increase_limit.
  Without this fix, the env variable RUBY_GC_OLDMALLOC_LIMIT
  does not work.
* gc.c (get_envparam_int): accept a value equals to lowerbounds.
* gc.c (get_envparam_double): ditto.



git-svn-id: svn+ssh://svn.ruby-lang.org/ruby/trunk@44853 b2dd03c8-39d4-4d8f-98ff-823fe69b080e