Build-test "core" packages on ghc-9.4 about gentoo-haskell

[vimproved]

I've managed to build all of these, barring dev-vcs/darcs (requires text <2) and x11-misc/xmobar (dev-haskell/glib is broken on musl).

Here are logs for test failures:
dev-haskell/crypton: https://0x0.st/HyuL.log
dev-haskell/crypton-x509-validation: https://0x0.st/Hyu9.log
dev-haskell/hslua-core: https://0x0.st/Hyup.log
dev-haskell/tls: https://0x0.st/Hyuf.log
dev-haskell/tz (probably caused by musl): https://0x0.st/HyuO.log
dev-haskell/tzdata (probably caused by musl): https://0x0.st/HyuV.log
dev-haskell/unix-time: https://0x0.st/HyuW.log
x11-misc/arbtt (definitely caused by musl): https://0x0.st/Hyu4.log

This also requires a fix for dev-haskell/generic-lens that I have not pushed yet.