Fix ghcjs 8.6.5 and 8.8.4 (#1447)

Also hydra now builds ghcjs 8.8.4, 8.6.5 and 8.10.7 on x86_64-linux build ghcjs 8.10.7 on x86_64-darwin

Author: hamishmack

ci.nix

@@ -58,7 +58,9 @@
     # We need to use the actual nixpkgs version we're working with here, since the values
     # of 'lib.systems.examples' are not understood between all versions
     let lib = nixpkgs.lib;
-    in lib.optionalAttrs (nixpkgsName == "unstable" && (__elem compiler-nix-name ["ghc8107"]) && system != "aarch64-darwin") {
+    in lib.optionalAttrs (nixpkgsName == "unstable"
+      && ((system == "x86_64-linux"  && __elem compiler-nix-name ["ghc865" "ghc884" "ghc8107"]) 
+       || (system == "x86_64-darwin" && __elem compiler-nix-name ["ghc8107"]))) {
     inherit (lib.systems.examples) ghcjs;
   } // lib.optionalAttrs (system == "x86_64-linux" &&
          nixpkgsName == "unstable" && (__elem compiler-nix-name ["ghc8107"])) {

lib/ghcjs-project.nix

@@ -50,6 +50,7 @@
     cabalProjectLocal = ''
       constraints: Cabal <3.2.1.0
     '';
+    modules = [{ reinstallableLibGhc = true; }];
     materialized = ../materialized/ghcjs/cabal + "/${compiler-nix-name}";
   }
 , ...