merge revision(s) 40000: [Backport #8097]

	* thread.c (rb_mutex_synchronize_m): yield no block params.  patch by
	  splattael (Peter Suschlik) in [ruby-core:53773] [Bug #8097].
	  fix GH-266.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@40380 b2dd03c8-39d4-4d8f-98ff-823fe69b080e