We should add FAIL_ON_WARNINGS = 1 to hal/Makefile.in to make sure the directory stays warning-free.
Naive attempt here: https://tbpl.mozilla.org/?tree=Try&rev=b7bc387be59b
All builds are okay except on MacOS. Hopefully that one will be green: https://tbpl.mozilla.org/?tree=Try&rev=649ecfa1f675 (it is including the two smslib fixes)
Created attachment 640997 [details] [diff] [review] Patch This is passing try.