mutex_m.rb -
	$Release Version: 3.0$
	$Revision: 1.7 $
    Original from mutex.rb
	by Keiju ISHITSUKA(keiju@ishitsuka.com)
    modified by matz
    patched by akira yamada

Usage:

require “mutex_m.rb” obj = Object.new obj.extend Mutex_m … extended object can be handled like Mutex

or

class Foo

include Mutex_m
...

end obj = Foo.new this obj can be handled like Mutex