So I've been working on both tmux and screen for IRIX. Spoiler: the situation ain't quite that good. Read on.
Good News
We have a version of screen:
http://irix.cc/raion/working/screen-4.0.3.tar.gz that works quite alright without any patches, on MIPSPro even.
Bad News
Post-Unicode tmux is unlikely to be usable. IRIX support was shelved in tmux in 2009, but I've never found any evidence that tmux works on any version, on any IRIX.
I did get far in tmux-0.8:
http://irix.cc/raion/failed-builds/tmux-...d-irix.tar
Here's where that's stuck:
https://pastebin.com/NgzuFEgf
There is an old forkpty-irix for tmux, and I added compatibility for asprintf and that fixed a number of issues. But it still won't compile with GCC, doesn't even get off the ground with mipspro. This is pre-unicode. Tmux 0.9 and up have really messed up build systems. I didn't document a lot of what I did as I was hyped up on caffeine and beer.
I managed to patch Screen 4.2.1 for IRIX/mipspro by adding a definition for SCM_RIGHTS to socket.c:
http://irix.cc/raion/buggy/screen-4.2.1.tar.gz
But it bitches about bad ttys when I try to run it. Strange. Not sure what that's about.
For now, I'm moving on for now. I think that it's possible to get both tmux and newer screen eventually working on IRIX, but I've got other things I can be doing with my time.
Hopefully this documents and helps along further efforts. I'm going to go back to other stuff I can do.
I'm the system admin of this site. Private security technician, licensed locksmith, hack of a c developer and vintage computer enthusiast.
https://contrib.irixnet.org/raion/ -- contributions and pieces that I'm working on currently.
https://codeberg.org/SolusRaion -- Code repos I control
Technical problems should be sent my way.