On AIX, access(X_OK) may succeed when run as root even if the
execution isn't possible. This behavior is allowed by POSIX
which says:
... for a process with appropriate privileges, an implementation
may indicate success for X_OK even if execute permission is not
granted to any user.
It can lead hook programs to have their execution refused:
git commit -m content
fatal: cannot exec '.git/hooks/pre-commit': Permission denied
Add NEED_ACCESS_ROOT_HANDLER in order to use an access helper function.
It checks with stat if any executable flags is set when the current user
is root.
Signed-off-by: Clément Chigot <clement.chigot@atos.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>