dxvk: rely on the cross support in nixpkgs

The `isCross` check is broken. When cross-compiling, it incorrectly
evaluates to false. DXVK has been building using the Meson
cross-compilation support in nixpkgs instead of with upstream’s cross
file. Instead of fixing `isCross`, just drop it as unnecessary.

pkgs/by-name/dx/dxvk_1/package.nix

@@ -9,9 +9,6 @@
 , enableMoltenVKCompat ? false
 }:
 
-let
-  isCross = stdenv.hostPlatform != stdenv.targetPlatform;
-in
 stdenv.mkDerivation (finalAttrs:  {
   pname = "dxvk";
   version = "1.10.3";
@@ -36,15 +33,10 @@ stdenv.mkDerivation (finalAttrs:  {
   nativeBuildInputs = [ glslang meson ninja ];
   buildInputs = [ windows.pthreads ];
 
-  mesonFlags =
-    let
-      arch = if stdenv.is32bit then "32" else "64";
-    in
-    [
-      "--buildtype" "release"
-      "--prefix" "${placeholder "out"}"
-    ]
-    ++ lib.optionals isCross [ "--cross-file" "build-win${arch}.txt" ];
+  mesonFlags = [
+    "--buildtype" "release"
+    "--prefix" "${placeholder "out"}"
+  ];
 
   meta = {
     description = "A Vulkan-based translation layer for Direct3D 9/10/11";

pkgs/by-name/dx/dxvk_2/package.nix

@@ -19,7 +19,6 @@
 assert !sdl2Support || !glfwSupport;
 
 let
-  isCross = stdenv.hostPlatform != stdenv.targetPlatform;
   isWindows = stdenv.hostPlatform.uname.system == "Windows";
 in
 stdenv.mkDerivation (finalAttrs:  {
@@ -51,18 +50,12 @@ stdenv.mkDerivation (finalAttrs:  {
     mkdir -p include/spirv/include include/vulkan/include
   '';
 
-  mesonFlags =
-    let
-      arch = if stdenv.is32bit then "32" else "64";
-    in
-    [
-      "--buildtype" "release"
-      "--prefix" "${placeholder "out"}"
-    ]
-    ++ lib.optionals isCross [ "--cross-file" "build-win${arch}.txt" ]
-    ++ lib.optional glfwSupport "-Ddxvk_native_wsi=glfw";
+  mesonFlags = [
+    "--buildtype" "release"
+    "--prefix" "${placeholder "out"}"
+  ] ++ lib.optional glfwSupport "-Ddxvk_native_wsi=glfw";
 
-  doCheck = !isCross;
+  doCheck = true;
 
   passthru.updateScript = gitUpdater { rev-prefix = "v"; };