DOS/Windows-specific code: ser-tcp.c

[Eli Zaretskii]

> 
> Btw, you seem to be working with an older version of the sources, Eli.
> I changed this __CYGWIN32__ to __CYGWIN__ a while ago.

That's true.  Unfortunately, I cannot afford resyncing with the CVS
frequently enough, and neither can I download the monster gdb+dejagnu
distros more than once in a long while: it takes about forever via my
dialup connection.  (Btw, the FTP site could use some improvement: it
is very slow.)

I apologize in advance for any inconvenience this might cause to those
of you who review the diffs.