Hi Mike, Everything you need to successfully build the Xerces-C library is now in the source, so if you can checkout the source from the anonymous cvs repository, you can build an IRIX version (using the MIPSpro 7.30 compilers, anyway).
Failing that, you can download version 1.1.0 source from the download page and follow the instructions given at http://fit.gmd.de/~mbaker/xerces-c-irix/ or http://www.esc.auckland.ac.nz/People/Students/Nickerso/Xerces-C/index.html to get it to work under IRIX. David.