SCO OpenServer 5.0.5 port

[mouring at etoh.eviladmin.org]

> Here is a patch to skip building sftp-server if there are no 64bit 
> data types.
> 
A version of this was applied.  There was a few minor things that needed
to be cleaned up (if sftp-server was not going to be installed then
sftp-server.8 is kinda worthless to install =).  Plus I added a warning at
the end to notify the person that sftp-server will not be installed.

> It also has some UnixWare 2.x fixes.
> 
Applied

- Ben