* rubysig.h (CHECK_INTS): gives the chance to perform to deferred
	  finalizers before explicit GC.start or the process termination.
	  [ruby-core:18045]
	* eval.c (rb_thread_schedule): runs deferred finalizers.
	* gc.c (gc_sweep): sets rb_thread_pending to run deferred finalizers.
	* rubysig.h (CHECK_INTS): now checks rb_thread_pending even on
	  platforms where setitimer is not available.  [ruby-core:18045]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8_7@21334 b2dd03c8-39d4-4d8f-98ff-823fe69b080e