gnuradio: fix cross compilation

pkgs/applications/radio/gnuradio/default.nix

···
       # when gr-qtgui is disabled, icu needs to be included, otherwise
       # building with boost 1.7x fails
       ++ lib.optionals (!(hasFeature "gr-qtgui")) [ icu ];
-      pythonNative = with python.pkgs; [
+      pythonNative = with python.pythonOnBuildForHost.pkgs; [
         mako
         six
       ];
···
         # This is the only python reference worth removing, if needed.
         + lib.optionalString (!hasFeature "python-support") ''
           remove-references-to -t ${python} $out/lib/cmake/gnuradio/GnuradioConfig.cmake
+        ''
+        + lib.optionalString (!hasFeature "python-support" && hasFeature "gnuradio-runtime") ''
           remove-references-to -t ${python} $(readlink -f $out/lib/libgnuradio-runtime${stdenv.hostPlatform.extensions.sharedLibrary})
           remove-references-to -t ${python.pkgs.pybind11} $out/lib/cmake/gnuradio/gnuradio-runtimeTargets.cmake
         '';

pkgs/applications/radio/gnuradio/shared.nix

···
     minor = builtins.elemAt (lib.splitVersion version) 2;
     patch = builtins.elemAt (lib.splitVersion version) 3;
   };
+  cross = stdenv.hostPlatform != stdenv.buildPlatform;
 in
 {
   src =
···
       ))
     ) featuresInfo
   );
-  cmakeFlags = lib.mapAttrsToList (
+  cmakeFlags = [
+    # https://pybind11.readthedocs.io/en/stable/changelog.html#version-2-13-0-june-25-2024
+    (lib.cmakeBool "CMAKE_CROSSCOMPILING" cross)
+    (lib.cmakeBool "PYBIND11_USE_CROSSCOMPILING" (cross && hasFeature "gnuradio-runtime"))
+  ]
+  ++ lib.mapAttrsToList (
     feat: info:
     (
       if feat == "basic" then