python313Packages.webrtc-noise-gain: fix cross builds (#375107)

pkgs/development/python-modules/webrtc-noise-gain/default.nix

@@ -28,6 +28,16 @@ buildPythonPackage rec {
     hash = "sha256-GbdG2XM11zgPk2VZ0mu7qMv256jaMyJDHdBCBUnynMY=";
   };
 
+  postPatch = with stdenv.hostPlatform.uname; ''
+    # Configure the correct host platform for cross builds
+    substituteInPlace setup.py --replace-fail \
+      "system = platform.system().lower()" \
+      'system = "${lib.toLower system}"'
+    substituteInPlace setup.py --replace-fail \
+      "machine = platform.machine().lower()" \
+      'machine = "${lib.toLower processor}"'
+  '';
+
   nativeBuildInputs = [
     pybind11
     setuptools