- Outright disable spammy warnings due to past or present GCC bugs:
* `-Wno-strict-overflow` for GCC 7.
* `-Wno-type-limits` for GCC before 11 (regressed in 9/10, might work in
earlier releases but at this stage we don't care).
* `-Wno-return-type` for GCC 12/13 (regression, still not fixed).
- Enable extra warnings conditionally when broken on earlier GCC:
* `-Wnoexcept` was removed due to an upstream regression in GCC 9, could
be re-enabled (but commented out for now as we actually have `-Wnoexcept`
warnings to fix.
* `-Wlogical-op` was broken on our variadic templates before GCC 11, now
seems fine.