2013-08-18  Tim Shen  <timshen91@gmail.com>

	* include/bits/regex_automaton.h: _S_opcode_backref.
	* include/bits/regex_automaton.tcc: Backref automaton support.
	* include/bits/regex_compiler.tcc: Parsing support.
	* include/bits/regex_executor.h: Add _M_traits for _DFSExecutor.
	* include/bits/regex_executor.tcc: Add _S_opcode_backref support.
	* testsuite/28_regex/algorithms/regex_match/ecma/string_backref.cc: New.

From-SVN: r201825