See attached build log.
(Please do not complain about the need for looking at the build log until you can provide an easy way to open bugs with the correct data picked out of a tinderbox log. Thanks.)
Created attachment 244075 [details]
This was a nasty one. Actually wmmaiload compilation failed, but a binary version was present in the tarball and got installed instead of our compiled one, and that version *accidentally* triggered this bug.