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 glibc's 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.
* lib/getopt_int.h: Remove all #ifdef USE_NONOPTION_FLAGS blocks.
* lib/getopt.c: Likewise. Also remove SWAP_FLAGS and the
__libc_argc and __libc_argv externs, which were only used by