Comment # 4 on bug 1171347 from Wolfgang Rosenauer

Good question. I am also struggling with Firefox builds once in a while because
of the huge resources required. (I even typically cannot even build FF locally
anymore as it's kills my machine until unrecoverable.)

So to summarize: I have no idea :-( Obviously TW changes and builds might start
failing for whatever reason. But if it works for you locally that is again a
different thing.
Wondering if disabling LTO would change anything since it seems to fail
somewhere around this?