(e.g. couldn't find original message).

Created xmodem_get_mode().

"sexyz -g rb" can also be used to enable Ymodem-G receives.
Using manual-reset outbuf_empty event.
Track and log flow control (outbuf full) instances.

(plus the NULL terminator). No functional change.

Eliminated non-standard fcloseall() call (should build on *nix now).

semwrap and are currently unused and untested (but *should* work)

set to an arbitrary value... make sem_reset() use this function.

Log and count file read errors.
More beautification.

utilization). We really need a cross-platform manually resetable boolean
semaphore (like a Windows "event").