Now logs port number, host name, and IP address for POP3 sessions where messages are either downloaded or deleted.

Put single quotes around unsupported command lprintf's to help debug extra white-space chars.

Changed algorithm for detect IP address vs host name (now supports hostnames starting with a digit).

Added comments and clarified the code a bit.
"real.name" and "sysop.alias" will retain original receipt names in message headers now (whoa).

This allows multiple instances with only one instance handling mail sends.

Changed use of select to time out every 2 seconds (allows detection of closed server socket on Unix).

Utilized PLATFORM_DESC in plublicly displayed version information in FTP and Mail servers.

This is apparently the only way to generated MSVC __cdecl-compatible names.
The stack maintenance isn't supposed to be compatible, but it appears to work. <shrug>

Displays startup time using lprintf for time-zone verification.
cleanup() doesn't call WSACleanup unless WinSock has been initialized.

New feature: mail_startup_t.relay_port = configurable TCP port for SMTP relay server (previously hard-coded to 25).

Created system call wrappers.c (and sbbswrap.h) and moved target platform-specific macros and code there.