Bug#1051493: ghc: FTBFS with a GHC newer than 9.0.2

[Ilias Tsitsimpis]

Source: ghc
Version: 9.4.6-1
Severity: serious
Tags: ftbfs
Justification: FTBFS

The current version of GHC in unstable (9.4.6-1) FTBFS when the
bootstrap compiler is newer than 9.0.2.

The error message is the following:

  ghc.mk:141: *** The make build system requires a boot compiler older
  than ghc-9.2. Your boot compiler is too new and cannot be used to
  build ghc-9.4 with make. Either boot with ghc 9.0.2 or build with
  hadrian. See
  https://www.haskell.org/ghc/blog/20220805-make-to-hadrian.html for
  advice on transitioning to hadrian..  Stop.

We need to switch to the newer hadrian build system in order to be able
to build ghc with a newer bootstrap compiler.

For more information about why the make build system fails, see the
upstream issue https://gitlab.haskell.org/ghc/ghc/-/issues/21188.

Thanks,

-- 
Ilias