Previously we would use whatever version was in nixpkgs yet this may not
be the version which the patch is supposed to be applied against.

Thanks to vaibhavsagar for the update script [1].

[1] https://github.com/vaibhavsagar/experiments/blob/f3f807212b82f07485c3df041cd8d6236ecb94e2/bump-all-cabal-hashes/updater

- v2-update is preferred (i.e. `v2-` prefix)
- but it's actually broken, due still existing `cabal-install` bug in
  non-append repository updates
- Also add explicit link to haskell.gitlab.com

Patch libraries to work with GHC 8.9

See merge request ghc/head.hackage!8

Add sop-core-0.5.0.0 patch

See merge request !7

nix: Rip out brokenPackages

See merge request ghc/head.hackage!6

Test all packages with patches

See merge request !5

This fixes the bindist versioning logic.

Otherwise the ret variable isn't captured in the parent environment.

From streaming commit a59174400842f6446eefd4b83e1951696ecdf4e1

Allow additional arguments to be passed to GHC

See merge request !4