* include/features.h: If no feature selection given and we select

* include/features.h: If no feature selection given and we select

	by default a POSIX mode, also define __USE_POSIX_IMPLICITLY.
	* posix/Versions: Export __posix_getopt.
	* posix/getopt.c (_getopt_initialize): Take additional parameter.
	Use it to alternatively initialize __posixly_correct.
	(_getopt_internal_r): Take addition parameter.  Pass on to
	_getopt_initialize.
	(_getopt_internal): Take addition parameter.  Pass on to
	_getopt_internal_r.
	(getopt): Pass additional zero to _getopt_internal.
	(__posix_getopt): New function.
	* posix/getopt.h: Add redirection for getopt.
	* posix/getopt1.c (getopt_long): Pass additional zero to
	_getopt_internal.
	(getopt_long_only): Likewise.
	(_getopt_long_r): Pass additional zero to _getopt_internal_r.
	(_getopt_long_only_r): Likewise.
	* posix/getopt_int.h: Adjust declarations of _getopt_internal and
	_getopt_internal_r.