PR libstdc++/63219
	* include/bits/regex.h (match_results::format): Remove stray template
	parameter.
	* include/bits/regex_compiler.h (_RegexTranslator::_RegexTranslator):
	Remove parameter name to avoid -Wunused-parameter warning.
	* include/bits/regex_executor.h (_State_info::_State_info): Reorder
	mem-initializers to avoid -Wreorder warning.
	* include/bits/regex_executor.tcc (_Executor::_M_word_boundary):
	Remove parameter name to avoid -Wunused-parameter warning.
	* include/bits/regex_scanner.tcc (_Scanner::_M_advance): Add braces
	to avoid -Wempty-body warning when not in debug mode.

From-SVN: r215160