Since - IRIX 6.5 is end-of-life for more than 10 years [1], - I don't have access to an IRIX machine any more, - the AC_SYS_LARGEFILE macro no longer supports IRIX, I would suggest to remove mentions of IRIX support from the documentation. Like we did for OSF/1 in 2019:
doc: Remove documentation of OSF/1 as supported platform. * doc/gnulib-intro.texi (Target Platforms): Mention that OSF/1 is unsupported. ... * doc/**/*.texi: Update. Any objections? Bruno [1] https://git.savannah.gnu.org/gitweb/?p=gnulib/maint-tools.git;a=blob;f=end-of-life.txt