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

[Andrew Cagney]

>  * ser-tcp.c:
> 
> #ifndef __CYGWIN32__
> #include <netinet/tcp.h>
> #endif
> 
> Is netinet/tcp.h header specific to Cygwin? If so, this could be
> replaced by a HAVE_NETINET_TCP_H macro set by Autoconf.

The lack of it?  Yes that looks to be unique to cygwin.  HAVE_... should 
be sufficient.

	Andrew