cproc/arg.h -rw-r--r-- 432 bytes
Handle argv = { NULL } in ARGBEGIN
Minor tweaks to arg.h

Make sure EARGF() has type `char *` (rather than `void *`).

Only advance opt_ when there is more left in the argument.
arg: Use (void *)0 instead of NULL in error case of conditional expression

Even though NULL is a null pointer constant, the comma expression with
NULL at the end is not. So, we must ensure that either the type of the
comma expression is `char *` or `void *`, and we don't know this for NULL.