flutter: revert remove usages of aliases {build,host,target}Platform

PR #350299 broke Flutter's update script with how it handled getting the
platform. Furthermore, the problem was made worse in the last update to
Flutter which had to work around that problem. We'll just revert it for
now and do a proper fix once we can figure out how to satify setting the
different platforms without causing any more problems.

pkgs/development/compilers/flutter/engine/package.nix

···
   darwin,
   clang,
   llvm,
-  tools ? callPackage ./tools.nix { },
+  tools ? callPackage ./tools.nix {
+    inherit (stdenv)
+      hostPlatform
+      buildPlatform
+      ;
+  },
   stdenv,
   stdenvNoCC,
   dart,
···
       version
       hashes
       url
+      ;
+    inherit (stdenv)
+      hostPlatform
+      buildPlatform
+      targetPlatform
       ;
   };
 

pkgs/development/compilers/flutter/engine/source.nix

···
 {
-  stdenv,
   lib,
   callPackage,
   fetchgit,
···
   version,
   hashes,
   url,
+  hostPlatform,
+  targetPlatform,
+  buildPlatform,
 }@pkgs:
 let
-  target-constants = callPackage ./constants.nix { platform = stdenv.targetPlatform; };
-  build-constants = callPackage ./constants.nix { platform = stdenv.buildPlatform; };
-  tools = pkgs.tools or (callPackage ./tools.nix { });
+  target-constants = callPackage ./constants.nix { platform = targetPlatform; };
+  build-constants = callPackage ./constants.nix { platform = buildPlatform; };
+  tools = pkgs.tools or (callPackage ./tools.nix { inherit hostPlatform buildPlatform; });
 
   boolOption = value: if value then "True" else "False";
 in
-runCommand
-  "flutter-engine-source-${version}-${stdenv.buildPlatform.system}-${stdenv.targetPlatform.system}"
+runCommand "flutter-engine-source-${version}-${buildPlatform.system}-${targetPlatform.system}"
   {
     pname = "flutter-engine-source";
     inherit version;
···
         "custom_vars": {
           "download_fuchsia_deps": False,
           "download_android_deps": False,
-          "download_linux_deps": ${boolOption stdenv.targetPlatform.isLinux},
+          "download_linux_deps": ${boolOption targetPlatform.isLinux},
           "setup_githooks": False,
           "download_esbuild": False,
           "download_dart_sdk": False,
···
     outputHashAlgo = "sha256";
     outputHashMode = "recursive";
     outputHash =
-      (hashes."${stdenv.buildPlatform.system}" or { })."${stdenv.targetPlatform.system}"
-        or (throw "Hash not set for ${stdenv.targetPlatform.system} on ${stdenv.buildPlatform.system}");
+      (hashes."${buildPlatform.system}" or { })."${targetPlatform.system}"
+        or (throw "Hash not set for ${targetPlatform.system} on ${buildPlatform.system}");
   }
   ''
     source ${../../../../build-support/fetchgit/deterministic-git}

pkgs/development/compilers/flutter/engine/tools.nix

···
 {
   stdenv,
+  buildPlatform,
+  hostPlatform,
   callPackage,
   fetchgit,
   fetchurl,
···
   },
 }:
 let
-  constants = callPackage ./constants.nix { platform = stdenv.buildPlatform; };
-  host-constants = callPackage ./constants.nix { platform = stdenv.hostPlatform; };
+  constants = callPackage ./constants.nix { platform = buildPlatform; };
+  host-constants = callPackage ./constants.nix { platform = hostPlatform; };
   stdenv-constants = callPackage ./constants.nix { platform = stdenv.hostPlatform; };
 in
 {

pkgs/development/compilers/flutter/update/get-engine-hashes.nix.in

···
           ++ (map
             (targetPlatform:
               callPackage "${nixpkgsRoot}/pkgs/development/compilers/flutter/engine/source.nix" {
-                stdenv = stdenv.override {
-                  targetPlatform = lib.systems.elaborate targetPlatform;
-                  hostPlatform = lib.systems.elaborate buildPlatform;
-                  buildPlatform = lib.systems.elaborate buildPlatform;
-                };
-
+                targetPlatform = lib.systems.elaborate targetPlatform;
+                hostPlatform = lib.systems.elaborate buildPlatform;
+                buildPlatform = lib.systems.elaborate buildPlatform;
                 flutterVersion = version;
                 version = engineVersion;
                 url = "https://github.com/flutter/engine.git@${engineVersion}";

pkgs/development/compilers/flutter/versions/3_24/data.json

···
       "x86_64-linux": "sha256-/jkMlcE0AZFWgTtUaUk8e/RxD31mObG91C6nfLzXdYU="
     },
     "x86_64-linux": {
-      "aarch64-linux": "sha256-/jkMlcE0AZFWgTtUaUk8e/RxD31mObG91C6nfLzXdYU=",
-      "x86_64-linux": "sha256-/jkMlcE0AZFWgTtUaUk8e/RxD31mObG91C6nfLzXdYU="
+      "aarch64-linux": "sha256-aQK3uD8n/V1ZH5+RbCNVZ1Fxx0Z33y5IEG4B0MVKh58=",
+      "x86_64-linux": "sha256-aQK3uD8n/V1ZH5+RbCNVZ1Fxx0Z33y5IEG4B0MVKh58="
     }
   },
   "dartVersion": "3.5.4",

pkgs/development/compilers/flutter/versions/3_26/data.json

···
       "x86_64-linux": "sha256-cDXCGikGuPWxMZZ0HWcnbS7Dt22no9wwbh4wei7w8Bw="
     },
     "x86_64-linux": {
-      "aarch64-linux": "sha256-cDXCGikGuPWxMZZ0HWcnbS7Dt22no9wwbh4wei7w8Bw=",
-      "x86_64-linux": "sha256-cDXCGikGuPWxMZZ0HWcnbS7Dt22no9wwbh4wei7w8Bw="
+      "aarch64-linux": "sha256-deuArmKBZvkjjt986wAAwGArKYMW01QvbgqzQ9FLBS8=",
+      "x86_64-linux": "sha256-deuArmKBZvkjjt986wAAwGArKYMW01QvbgqzQ9FLBS8="
     }
   },
   "dartVersion": "3.6.0-216.1.beta",

pkgs/development/compilers/flutter/versions/3_27/data.json

···
       "x86_64-linux": "sha256-xEUUengFzRbQhFB7jxTBd8eTMWUhyBTTKyT/ObuyD/o="
     },
     "x86_64-linux": {
-      "aarch64-linux": "sha256-xEUUengFzRbQhFB7jxTBd8eTMWUhyBTTKyT/ObuyD/o=",
-      "x86_64-linux": "sha256-xEUUengFzRbQhFB7jxTBd8eTMWUhyBTTKyT/ObuyD/o="
+      "aarch64-linux": "sha256-YFmK7eSt9lK/iEMPC5jxp5Vf2pnDjUDyPVoHzgxc8mA=",
+      "x86_64-linux": "sha256-YFmK7eSt9lK/iEMPC5jxp5Vf2pnDjUDyPVoHzgxc8mA="
     }
   },
   "dartVersion": "3.6.0-334.3.beta",