haskell.compiler.ghc{928,963,967,9101,9102,HEAD}: drop AArch32 bootstrap

It’s questionable whether or not this worked – 32‐bit ARM in
Nixpkgs is already flaky even when cross‐compiling, and I find
it dubious whether much 32‐bit ARM hardware can build modern
GHCs in a bearable amount of time and memory – and figuring out
cross‐compilation of bootstrap GHCs will be a more sustainable way
to keep it working if anyone cares enough to.

Also, rearrange the GHC‐related release notes to be in order of
most likely to matter to anyone.

doc/release-notes/rl-2511.section.md

@@ -24,11 +24,13 @@
 
 - GCC 9, 10, 11, and 12 have been removed, as they have reached end‐of‐life upstream and are no longer supported.
 
-- GHC 8.6 and its package set have been removed. It was only used to bootstrap GHC for powerpc64le, but this was probably broken anyway.
-
 - GHCJS 8.10, exposed via `haskell.compiler.ghcjs` and `haskell.compiler.ghcjs810`, has been removed. Downstream users should migrate their projects to the new JavaScript backend of GHC proper which can be used via `pkgsCross.ghcjs` from Nixpkgs. Haskell packaging code, like `haskellPackages.mkDerivation`, `ghcWithPackages` and `hoogleWithPackages`, also no longer supports GHCJS.
 
-- GHC 9.0 and its package set have been removed.
+- GHC 8.6, 9.0, and their package sets have been removed.
+
+- Support for bootstrapping native GHC compilers on 32‐bit ARM and little‐endian 64‐bit PowerPC has been dropped.
+  The latter was probably broken anyway.
+  If there is interest in restoring support for these architectures, it should be possible to cross‐compile a bootstrap GHC binary.
 
 - `base16-builder` node package has been removed due to lack of upstream maintenance.
 

pkgs/top-level/haskell-packages.nix

@@ -111,9 +111,7 @@ in
       };
       ghc810 = compiler.ghc8107;
       ghc928 = callPackage ../development/compilers/ghc/9.2.8.nix {
-        bootPkgs =
+        bootPkgs = bb.packages.ghc902Binary;
-          # GHC >= 9.0 removed the armv7l bindist
-          if stdenv.buildPlatform.isAarch32 then bb.packages.ghc8107Binary else bb.packages.ghc902Binary;
         inherit (buildPackages.python311Packages) sphinx; # a distutils issue with 3.12
         python3 = buildPackages.python311; # so that we don't have two of them
         # Need to use apple's patched xattr until
@@ -140,9 +138,7 @@ in
       };
       ghc94 = compiler.ghc948;
       ghc963 = callPackage ../development/compilers/ghc/9.6.3.nix {
-        bootPkgs =
+        bootPkgs = bb.packages.ghc924Binary;
-          # For GHC 9.2 no armv7l bindists are available.
-          if stdenv.buildPlatform.isAarch32 then bb.packages.ghc928 else bb.packages.ghc924Binary;
         inherit (buildPackages.python3Packages) sphinx;
         # Need to use apple's patched xattr until
         # https://github.com/xattr/xattr/issues/44 and
@@ -153,9 +149,7 @@ in
         llvmPackages = pkgs.llvmPackages_15;
       };
       ghc967 = callPackage ../development/compilers/ghc/9.6.7.nix {
-        bootPkgs =
+        bootPkgs = bb.packages.ghc924Binary;
-          # For GHC 9.2 no armv7l bindists are available.
-          if stdenv.buildPlatform.isAarch32 then bb.packages.ghc928 else bb.packages.ghc924Binary;
         inherit (buildPackages.python3Packages) sphinx;
         # Need to use apple's patched xattr until
         # https://github.com/xattr/xattr/issues/44 and
@@ -170,9 +164,6 @@ in
         bootPkgs =
           if stdenv.buildPlatform.isAarch64 && stdenv.buildPlatform.isMusl then
             bb.packages.ghc984Binary
-          else if stdenv.buildPlatform.isAarch32 then
-            # For GHC 9.6 no armv7l bindists are available.
-            bb.packages.ghc963
           else
             bb.packages.ghc963Binary;
         inherit (buildPackages.python3Packages) sphinx;
@@ -187,10 +178,7 @@ in
       ghc98 = compiler.ghc984;
       ghc9101 = callPackage ../development/compilers/ghc/9.10.1.nix {
         bootPkgs =
-          # For GHC 9.6 no armv7l bindists are available.
+          if stdenv.buildPlatform.isDarwin then
-          if stdenv.buildPlatform.isAarch32 then
-            bb.packages.ghc963
-          else if stdenv.buildPlatform.isDarwin then
             # it seems like the GHC 9.6.* bindists are built with a different
             # toolchain than we are using (which I'm guessing from the fact
             # that 9.6.4 bindists pass linker flags our ld doesn't support).
@@ -210,10 +198,7 @@ in
       };
       ghc9102 = callPackage ../development/compilers/ghc/9.10.2.nix {
         bootPkgs =
-          # For GHC 9.6 no armv7l bindists are available.
+          if stdenv.buildPlatform.isDarwin then
-          if stdenv.buildPlatform.isAarch32 then
-            bb.packages.ghc963
-          else if stdenv.buildPlatform.isDarwin then
             # it seems like the GHC 9.6.* bindists are built with a different
             # toolchain than we are using (which I'm guessing from the fact
             # that 9.6.4 bindists pass linker flags our ld doesn't support).
@@ -260,9 +245,7 @@ in
       };
       ghc912 = compiler.ghc9122;
       ghcHEAD = callPackage ../development/compilers/ghc/head.nix {
-        bootPkgs =
+        bootPkgs = bb.packages.ghc984Binary;
-          # No armv7l bindists are available.
-          if stdenv.buildPlatform.isAarch32 then bb.packages.ghc984 else bb.packages.ghc984Binary;
         inherit (buildPackages.python3Packages) sphinx;
         # Need to use apple's patched xattr until
         # https://github.com/xattr/xattr/issues/44 and