Comment 16 for bug 294437

Okay this is fixed by [2803], [2804], [2805], [2806], [2807]. (Changes to the build system sometimes take multiple patches, because I use the buildbot to try out my changes on all of our platforms at once. If the buildbot "try this out but don't commit it to trunk" feature were working and I knew how to use it then I would do that instead.)

The fix is to set --reactor=poll on linux. (So this is in a sense a work-around instead of a fix, but on the other hand there's no reason for us to prefer the select reactor on linux, so this is fine.)