exit: drop remaining clients

exit: drop remaining clients

Anyone using EXIT_FAILURE needs to depend on stdlib, now that
the exit module is gone.

* modules/argmatch (Depends-on): Replace exit with stdlib.
* modules/copy-file (Depends-on): Likewise.
* modules/execute (Depends-on): Likewise.
* modules/exitfail (Depends-on): Likewise.
* modules/obstack (Depends-on): Likewise.
* modules/pagealign_alloc (Depends-on): Likewise.
* modules/pipe-filter-gi (Depends-on): Likewise.
* modules/pipe-filter-ii (Depends-on): Likewise.
* modules/savewd (Depends-on): Likewise.
* modules/spawn-pipe (Depends-on): Likewise.
* modules/wait-process (Depends-on): Likewise.
* modules/xsetenv (Depends-on): Likewise.
* modules/chdir-long (Depends-on): Add stdlib, for EXIT_FAILURE.
* modules/git-merge-changelog (Depends-on): Likewise.
* modules/long-options (Depends-on): Likewise.
* modules/pt_chown (Depends-on): Likewise.
* modules/sysexits (Depends-on): Likewise.

Signed-off-by: Eric Blake <eblake@redhat.com>