ifconfig uses __caddr_t in one location; this is not guaranteed to work everywhere. It does not compile OOB on musl, so I changed it to the portable equivalent, char *.  This compiles on musl, and should compile anywhere.
Tweak help text.
Move guts of help command into show_help() in lib/help.c, with config TOYBOX_HELP controlling infrastructure.
Add tests for find's expression parsing