Build System Project - Latest Update

[David Burns]

Below is a highlight of all work the build peers have done since the last
report[1].

The build peers have been working to get faster builds in automation as
well as well as local developers. We are currently testing the distributed
cache rewrite (sccache) to make sure that we have not regressed anything.
Once this has landed we can start work on how it can benefit engineers
local environments. We have also been working to try get artifact builds
being used at least on Try in an attempt to bring down try turnaround times.

They have also been working through making 3rd party libraries build
faster. This is part of the work to remove the use of recursive make in our
build system which is going quite well. So well in fact we are now starting
work on prototyping a new build back end. Hopefully this prototype will be
done by the end of the quarter.

And finally our intern, Nathan, has done some great work with updating
MozillaBuild to msys2 and now has artifact builds working there.

[1]
https://groups.google.com/d/msg/mozilla.dev.platform/VH3KD4ZyNL0/befnqd7WPQAJ


David