Keep mingwW64 target to ghc96

flake.nix

@@ -26,7 +26,7 @@
     # see flake `variants` below for alternative compilers
     defaultCompiler = "ghc982";
     haddockShellCompiler = defaultCompiler;
-
+    mingwVersion = "ghc965";
     cabalHeadOverlay = final: prev: {
       cabal-head =
         (final.haskell-nix.cabalProject {
@@ -85,7 +85,7 @@
 
           # we also want cross compilation to windows on linux (and only with default compiler).
           crossPlatforms = p:
-            lib.optional (system == "x86_64-linux" && config.compiler-nix-name == defaultCompiler)
+            lib.optional (system == "x86_64-linux" && config.compiler-nix-name == mingwVersion)
             p.mingwW64;
 
           # CHaP input map, so we can find CHaP packages (needs to be more
@@ -167,7 +167,7 @@
         flake = cabalProject.flake (
           lib.optionalAttrs (system == "x86_64-linux") {
             # on linux, build/test other supported compilers
-            variants = lib.genAttrs ["ghc8107"] (compiler-nix-name: {
+            variants = lib.genAttrs ["ghc8107" "ghc964"] (compiler-nix-name: {
               inherit compiler-nix-name;
             });
           }