Last week, I was trying to fix a non-unified build bustage with glandium’s help and I kept failing to fix it in mozilla-inbound. I don’t usually build locally myself, so I had to push to Try. And there was no documentation on how-to do it. It turns out that it needs a custom mozconfig override (thanks dbaron).
You need to add
ac_add_options --disable-unified-compilation to the file
build/mozconfig.common.override in one of your pushes. Probably easier, if it’s the tip. We updated the wiki with this small piece of documentation.
This is mostly a note to myself. And perhaps for contributors who might search for it.