regex.h: Add friend classes.

regex.h: Add friend classes.

2013-09-18  Tim Shen  <timshen91@gmail.com>

	* include/bits/regex.h: Add friend classes.
	(match_results<>::position, regex_iterator<>::operator++):
	Implement position specification in regex_iterator.
	(regex_match<>, regex_search<>):
	Move match_results initializations to these function. Remove `todo`.
	* include/bits/regex_compiler.tcc:
	(_Compiler<>::_M_quantifier): Fix greedy/ungreedy of interval matching.
	* include/bits/regex_constants.h:
	Fix indentation. Change match_flag_type to enum type.
	* include/bits/regex_executor.h:
	Merge identical code to the base class _Executor.
	Support flags in regex_constants.
	* include/bits/regex_executor.tcc: Likewise.
	* include/bits/regex_scanner.h: Add comments.
	* include/bits/regex_scanner.tcc: Same.
	* testsuite/28_regex/algorithms/regex_search/ecma/assertion.cc:
	Add a testcase.
	* testsuite/28_regex/algorithms/regex_search/ecma/flags.cc: New.
	* testsuite/28_regex/iterators/regex_iterator/char/
	string_position_01.cc: Remove `xfail`.
	* testsuite/28_regex/iterators/regex_iterator/wchar_t/string_02.cc:
	Remove `xfail` and make the case really work.

From-SVN: r202706