Re: RFC: Remove documentation of IRIX as supported platform

[Paul Eggert]

This sounds good to me.

As far as IRIX goes, AC_SYS_LARGEFILE still works on 64-bit IRIX. Even 
32-bit IRIX should still work if you configure with CC='cc -n32', and 
this should be adequate for hobbyists who want to keep IRIX 5.3 going 
(some, by reverse engineering it! 
<https://tedium.co/2023/05/27/sgi-irix-revival-efforts/>).