-As much as possible I've attempted to stick to `doas` as tedu desired
-it. As things stand it's essentially just code lifted from OpenBSD with
-PAM or shadow based authentication glommed on to it.
-
-Compatibility functions in libopenbsd come from openbsd directly
-(`strtonum.c`, `reallocarray.c`, `strlcpy.c`, `strlcat.c`),
-from openssh (`readpassphrase.c`) or from sudo (`closefrom.c`).