Upgrade of Haskell stack

[liontiger23]

Motivation

Current ghc in repos is 9.4.8 (uses base 4.17), which was recommended version by GHCup project for a while.
However, now the recommended version is 9.6.7 (uses base 4.18) and some of our packages require even higher GHC version: for example, pandoc-crossref 0.3.22 requires GHC 9.8.* (uses base 4.19).

Moreover, I think it makes sense to try to use the newest GHC version that we can as our build tool, to simplify future package updates and anticipate stack upgrade problems.

Reducing stack size

Currently we have a lot of intermediate haskell-* packages, which are dynamically linked only into couple of real packages haskell-cabal-install and xmonad/xmonad-contrib with haskell-cabal-install requiring majority of these packages:

Before upgrading GHC to any version we should build haskell-cabal-install using static linking, thus eliminating the need for most of these packages.

The whole Haskell stack (build dependencies) then would look like this:

xmonad

We probably could not switch xmonad to static linking, because its configuration is written in Haskell and requires availability of some haskell-* dependencies.
However, there is some argument to dropping xmonad altogether and letting users build it from source using official build guide or maybe providing some Solus specific instructions in help center.

Plan

• Reduce stack size: eliminate most of haskell-* packages by statically linking haskell-cabal-install
  • macros: prepare haskell macros for cabal-install 3.12 update ypkg#123
  • haskell-cabal-install: Update to v3.12.1.0 #6769
  • Deprecate obsolete haskell-cabal-install dependencies #6770
• Upgrade ghc to 9.8.4

  Note: GHC 9.10+ versions cannot be build with our current GHC 9.4.8, so we will still need such intermediate upgrade to either 9.6.7 or 9.8.4 for future versions

  • macros: prepare haskell macros for GHC 9.8 update ypkg#128
  • ghc: Update to v9.8.4 #6960
• Upgrade unblocked packages in the stack
  • Update pandoc and pandoc-crossref #7024
• Consider upgrading ghc to 9.12.2

[liontiger23]

Decided to document current plan for Haskell upgrades.
@GZGavinZhao please take a look