On Irix, using cc 7.4.2m, you must use -O1 (or lower)
If you use -O2 or -O3 then you will get a SIGSEGV in
XmlInitUnknownEncoding (lib/xmltok.c - line ~1363) when
running the test for XML-Parser-2.34.
(Looks like a compiler optimization bug - the problem
also goes away if you put any printf statements in
there to see what is happening)