PR79017 workaround incomplete C99 math on darwin

PR79017 workaround incomplete C99 math on darwin

	PR libstdc++/79017
	* acinclude.m4 (GLIBCXX_CHECK_C99_TR1): Check for llrint and llround
	functions separately on darwin and if they're missing define
	_GLIBCXX_NO_C99_ROUNDING_FUNCS.
	* config.h.in: Regenerate.
	* configure: Regenerate.
	* include/c_global/cmath [_GLIBCXX_NO_C99_ROUNDING_FUNCS] (llrint)
	(llrintf, llrintl, llround, llroundf, llroundl): Do not define.

From-SVN: r244231