I haven't (yet) worked on making an OS X job for Hadrian. I brought back the Windows/Hadrian CI job with that fix, but then tried running the testsuite, which didn't go well, see:

https://gitlab.haskell.org/ghc/ghc/merge_requests/1035

https://gitlab.haskell.org/alp/ghc/-/jobs/87467

This seems to have brought back a problem that Ben and I started looking into and which led us to disabling that job in the first place... However, running the testsuite is one thing, but just making sure we can build GHC is another.

I guess I can put together a patch to get us an OS X job that just builds GHC pretty quickly, and then later get both the Windows and OS X jobs to go as far as running the testsuite. That'd at least give us confidence that people can build GHC with Hadrian just fine on OS X.

Regarding the resources, that certainly sounds like something that would help if we are to double the number of OS X builds, indeed. I'm sure Ben (cc'd), who handles those matters, would be happy to talk about this with you!

In the meantime, I will prepare a patch to add an OSX/Hadrian job.