builtins.def (BUILT_IN_CABS, [...]): New builtins representing ISO C99's cabs, cabsf...

builtins.def (BUILT_IN_CABS, [...]): New builtins representing ISO C99's cabs, cabsf and cabsl.

	* builtins.def (BUILT_IN_CABS, BUILT_IN_CABSF, BUILT_IN_CABSL):
	New builtins representing ISO C99's cabs, cabsf and cabsl.
	* builtins.c (expand_builtin_fabs): New function.
	(expand_builtin_cabs): New function.
	(expand_builtin): Expand BUILT_IN_FABS{,F,L} and BUILT_IN_CABS{,F,L}
	using expand_builtin_fabs and expand_builtin_cabs respectively.

	* doc/extend.texi: Document new cabs, cabsf and cabsl builtins.

	* gcc.dg/builtins-16.c: New test case.

From-SVN: r67368