Support GHC 9.10

[tomjaguarpaw]

Initial conversion to GHC 9.10 is on branch 9.10. Test it with

cabal test -w ghc-9.10 --allow-newer

There are a number of test failures, so I suspect that the GHC API format has changed again :(

---

Any volunteers to take this on? @0rphee, would you be interested?

[0rphee]

I'm busy with school (approaching finals), so I'm afraid it would have to wait for a ~month (+/-)... :(

[tomjaguarpaw]

OK, no problem. Let's see if anyone else picks it up in the meantime. Good luck with finals!

[tomjaguarpaw]

This branch seems to work. It needs CPP in order to enable the changes for 9.10 only.

https://github.com/kowainik/stan/tree/9.10

[philderbeast]

I gave stan an Updo conversion and have it building there, at up-do/stan. I haven't tackled the test failures.

The conversion was interesting, see cabalism/updo#41. I went with a ghc-9.10.1 Stack resolver.

GHC_VERSION ?= 9.10.1
STACKAGE_VERSION ?= ghc-9.10.1

[tomjaguarpaw]

The test failures for 9.10 are fixed by my branch (see above), but it needs some CPP to make those changes only on 9.10.

[tomjaguarpaw]

After 09b1c66 we support 9.10. There's still one thing to be taken care of though: #572