qt6: backport patches recommended by KDE folks (#379692)

pkgs/development/libraries/qt-6/modules/qtbase/default.nix

@@ -82,6 +82,7 @@
   libGLSupported ? stdenv.hostPlatform.isLinux,
   libGL,
   qttranslations ? null,
+  fetchpatch,
 }:
 
 let
@@ -226,6 +227,20 @@ stdenv.mkDerivation rec {
     ./qmlimportscanner-import-path.patch
     # don't pass qtbase's QML directory to qmlimportscanner if it's empty
     ./skip-missing-qml-directory.patch
+
+    # FIXME: 6.8.3 backports recommended by KDE
+    (fetchpatch {
+      url = "https://invent.kde.org/qt/qt/qtbase/-/commit/12d4bf1ab52748cb84894f50d437064b439e0b7d.patch";
+      hash = "sha256-HBwmQyAyaJh+in50Kd+mMa/6t+GZC3UmQWSe7Ugvn2Y=";
+    })
+    (fetchpatch {
+      url = "https://invent.kde.org/qt/qt/qtbase/-/commit/2ef615228bba9a8eb282437bfb7472f925610e89.patch";
+      hash = "sha256-pkKA7o7er9n5mu8EfJsjs8NeEq/SlKpEoRZwsDor1+c=";
+    })
+    (fetchpatch {
+      url = "https://invent.kde.org/qt/qt/qtbase/-/commit/a43c7e58046604796aa69974ea1c5d3e2648c755.patch";
+      hash = "sha256-4KJn7RTpSi8IFUElt3LEoMsuJmkYSf+bp2/Jmf42Ygs=";
+    })
   ];
 
   postPatch = lib.optionalString stdenv.hostPlatform.isDarwin ''