getopt with gcc -ansi

[Paul Eggert]

Andreas Schwab <schwab@suse.de> writes:

> sleep is allowed everywhere <unistd.h> is allowed, but not getopt.

But in POSIX 1003.1-2004, getopt and sleep are both required functions
on the same footing; neither is an XSI extension, for example.
Perhaps this wasn't true in older POSIX revisions, but it's true now.
The "-ansi" flag should affect only the C standard level, not the
POSIX revision level, no?