Getting this working on Solaris/SunOS again

[fullspectrumdev]

Self-assigning this one, just putting it here in case you have any previous iterations that do work on Solaris/SunOS in your archives.

I'm attempting to get this working on a Solaris 9 (SPARC) VM I have, currently it is not building, but that could be down to the absolutely braindead compiler packages in my VM that I probably need to fix.

[stealth]

The project is 20y old and there was a time when it nicely worked on Solaris :)
As there are no external deps and its ISO C++ code, it should build nicely.
The only thing that could be different is pty handling. If that old Solaris does not support POSIX pty functions, check enabling OLD_BSD_PTY and disable HAVE_UNIX98 during build (check pty.cc, pty98.cc)