Btw. I did lots of (Linux) cross-builds for X almost decade ago.
There are also other build environment bugs into which X builds
can fail, than make segfaults.
It seemed that several of the terminal programs had such pty signaling
handling / console output buffering combination, that it interrupted
X builds. If you ever come across mystery X build failures, you could
try doing it in another console. I would e.g. never even try to build
X in TosWin... :-)
(I'm sure the bug could also be triggered by other SW than X, but
X was the only one with which I got it, reproducably.)
- Eero