getopt: remove USE_NONOPTION_FLAGS

getopt: remove USE_NONOPTION_FLAGS

glibc's implementation of getopt includes code to parse an environment
variable named _XXX_GNU_nonoption_argv_flags_ (where XXX is the
current process's PID in decimal); but all of it has been #ifdefed out
since 2001, with no official way to turn it back on.

According to commentary in our config.h.in, bash version 2.0 set this
environment variable to indicate argv elements that were the result of
glob expansion and therefore should not be treated as options, but the
feature was "disabled later" because "it caused problems".  According
to bash's CHANGES file, "later" was release 2.01; it gives no more
detail about what the problems were.

Version 2.0 of bash was released on the last day of 1996, and version
2.01 in June of 1997.  Twenty years later, I think it is safe to
assume that this environment variable isn't coming back.

	* config.h.in (USE_NONOPTION_FLAGS): Remove.
	* csu/init-first.c: Remove all #ifdef USE_NONOPTION_FLAGS blocks.
	* sysdeps/mach/hurd/i386/init-first.c: Likewise.
	* posix/getopt_int.h: Likewise.
	* posix/getopt.c: Likewise. Also remove SWAP_FLAGS and the
	__libc_argc and __libc_argv externs, which were only used by
	#ifdef USE_NONOPTION_FLAGS blocks.
	* posix/getopt_init.c: Remove file.
	* posix/Makefile (routines): Remove getopt_init.
	* include/getopt.h: Don't declare __getopt_initialize_environment.
	* manual/getopt.texi: Remove mention of USE_NONOPTION_FLAGS in
	a comment.