sayuri: Use mesa clover as OpenCL implementation

machines/sayuri/hardware-configuration.nix

@@ -68,9 +68,25 @@
   powerManagement.cpuFreqGovernor = lib.mkDefault "performance";
 
   # GPU
-  hardware.opengl.extraPackages = with pkgs; [
-    rocm-opencl-icd
-  ];
+  hardware.opengl =
+    let
+      # nixpkgs PR adding mesa clover support
+      # (https://github.com/NixOS/nixpkgs/pull/82729) rebased onto nixos-21.05
+      pkgsMesaClover = import
+        (pkgs.fetchFromGitHub {
+          owner = "sbruder";
+          repo = "nixpkgs";
+          rev = "e2894ba6626028e081b8ff124a39d2b523a0371c";
+          sha256 = "sha256-brM17UTESqtJ8jXbBAl2xDW7ziCBWROb2W+06vIEfjU=";
+        })
+        { inherit (pkgs) system; };
+    in
+    {
+      package = pkgsMesaClover.mesa_opencl.drivers;
+      extraPackages = [
+        pkgsMesaClover.mesa_opencl
+      ];
+    };
 
   environment.systemPackages = with pkgs; [
     clinfo