Fix cabal-simple test

Author: hamishmack

builder/comp-builder.nix

@@ -281,8 +281,11 @@ let
                      if builtins.isFunction shellHook then shellHook { inherit package shellWrappers; }
                      else abort "shellHook should be a string or a function";
 
-  exeExt = if stdenv.hostPlatform.isGhcjs && builtins.compareVersions defaults.ghc.version "9.8" < 0
-    then ".jsexe/all.js"
+  exeExt =
+    if stdenv.hostPlatform.isWasm
+      then ".wasm"
+    else if stdenv.hostPlatform.isGhcjs && builtins.compareVersions defaults.ghc.version "9.8" < 0
+      then ".jsexe/all.js"
     else stdenv.hostPlatform.extensions.executable;
   exeName = componentId.cname + exeExt;
   testExecutable = "dist/build/${componentId.cname}/${exeName}";

overlays/wasm.nix

@@ -40,4 +40,14 @@ final: prev: prev.lib.optionalAttrs prev.stdenv.targetPlatform.isWasm {
     '';
     nativeBuildInputs = old.nativeBuildInputs or [] ++ [ final.buildPackages.lld ];
   });
+
+  haskell-nix = prev.haskell-nix // ({
+    defaultModules = prev.haskell-nix.defaultModules ++ [
+      ({ pkgs, ... }: {
+        testWrapper = ["HOME=$(mktemp -d)" (pkgs.pkgsBuildBuild.wasmtime + "/bin/wasmtime")];
+        package-keys = ["clock"];
+        packages.clock.configureFlags = ["--ghc-option=-optc-Wno-int-conversion"];
+      })
+    ];
+  });
 }