[ruby-cvs:60150] nobu:r52997 (trunk): Revert r52995

[nobu at ruby-lang.org]

nobu	2015-12-09 16:30:44 +0900 (Wed, 09 Dec 2015)

  New Revision: 52997

  http://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=revision&revision=52997

  Log:
    Revert r52995
    
    revert slow atomic operations.

  Modified files:
    trunk/ChangeLog
    trunk/common.mk
    trunk/regcomp.c
    trunk/regint.h
    trunk/regparse.c
    trunk/ruby_atomic.h