Imminent Removal of Make Build System

[Matthew Pickering]

Hi all,

We are imminently going to remove the make build system.

See: https://gitlab.haskell.org/ghc/ghc/-/merge_requests/7094

There is quite extensive documentation about using hadrian, the best
place to start is the in-tree documentation:

https://gitlab.haskell.org/ghc/ghc/-/blob/master/hadrian/README.md

For packagers:

* The 9.4.* series will be the last release series which can be built
with the make build system.
* 9.6.* will only be able to be built using hadrian.
* See ghcs-nix for an example of how to modify your own build system
to use hadrian:
https://gitlab.haskell.org/bgamari/ghcs-nix/-/blob/master/hadrian.nix
* Sam Derbyshire is creating a guide aimed at packagers describing how
to migrate their build plans.

Cheers,

Matt