Abstract: headers are there, not much else.
I moved the IDO 5.3 IRIX4 files over to my P.I. and started playing around with them, and
there is mixed news. Bits of IDO4.1 (the recommended IDO for IRIX 4)
are there, including headers and cc, but other bits are missing (make, gendist, and other
stuff that make life easier.) So news is mixed: it looks like you could
concievably use the IRIX4 files on the freely-distributable IDO 5.3 to get a lot closer to
having a development environment on IRIX 4.0.x, but you'll still need to supplement
(big time) with GNU tools. I have the tarfile of the IRIX4 subrelease here if anyone wants
it, but I don't think I'll put too much more work into making it nice. I use 3.3.2
more
often on that machine, anyway. I believe there is also a way to cross-build on an IRIX 5
host.