* regex.c (xmalloc, xrealloc, xfree): not to use ruby managed memory.
	* regex.c (DOUBLE_STACK, re_compile_fastmap0, re_adjust_startpos),
	  (re_search, re_match_exec): check if failed to allocate memory.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8_6@18343 b2dd03c8-39d4-4d8f-98ff-823fe69b080e