upstream "do not test their builds with any of their allegedly 'optional' features disabled"

I've noticed this too and it's really annoying. Their CI doesn't even run `gn` for the use-flag permutations, which would take a trivial amount of compute. They could easily compile-but-not-link for every combination of flags in CI too at only a modest compute expenditure. At least that way people who break the #ifdef maze would be forced to fix it.