Experimenting with this in sbbs to see if there are any race conditions between
threads that manipulate the I/O buffers (e.g. Ctrl-C in input_thread clears
output buffer).

- disables Ctrl-C checking in input_thread (sets rio_abortable to false)
- sends Telnet "DONT BINARY" command after executing external program
- forces text attributes back to lightgray after executing external program

pass-through bitmap.

(was preliminarily named adduser).

with intercepted stdio (fix for downloads with sz).

bitmask.

multiple days of month on which to execute an event (or 0 for any).

(ctrl/mailproc.cfg).

parsing the header object parameter, to prevent duplicate header fields from
being saved back to the message base (bug reported by Guardian Angel).

pointers to freed memory (that might be accidentally dereferenced later).

(i.e. not the data fields). smb_freemsgmem() still frees both.

needs to seek backwards and write the header after the message text.

- prevents use of realpath_r() in single threaded utils.

thread-safe version of realpath() for OpenBSD builds, but normal version of
realpath() for single-threaded builds.

packet did not work at all and resulted in corrupted indexes (if enabled).
Updated brace style.

solve race condition that could occur if one server failed to initialize (e.g.
bind failure) causing other servers to fail to bind when running as user..

Added SBBS_SRC and XPDEV command-line switches to SBL make.

command-line.

command-line.