ghc:8.10.2Binary bootstrap for 8.8 on aarch64 (NixOS#97407)

pkgs/development/compilers/ghc/8.8.4.nix

@@ -119,7 +119,11 @@ stdenv.mkDerivation (rec {
   postPatch = "patchShebangs .";
 
   # GHC is a bit confused on its cross terminology.
-  preConfigure = ''
+  preConfigure = stdenv.lib.optionalString stdenv.isAarch64 ''
+    # Aarch64 allow backward bootstrapping since earlier versions are unstable.
+    find . -name \*\.cabal\* -exec sed -i -e 's/\(base.*\)4.14/\14.16/' {} \; \
+      -exec sed -i -e 's/\(prim.*\)0.6/\10.8/' {} \;
+  '' + ''
     for env in $(env | grep '^TARGET_' | sed -E 's|\+?=.*||'); do
       export "''${env#TARGET_}=''${!env}"
     done