kwin: bypass environment variables from ld.so

Missing `TZDIR` would break plasmashell.

pkgs/desktops/plasma-5/kwin/default.nix

@@ -1,6 +1,6 @@
 {
   mkDerivation, lib,
-  extra-cmake-modules, kdoctools,
+  extra-cmake-modules, kdoctools, fetchpatch,
 
   epoxy, lcms2, libICE, libSM, libcap, libdrm, libinput, libxkbcommon, mesa,
   pipewire, udev, wayland, xcb-util-cursor, xwayland,
@@ -40,6 +40,15 @@ mkDerivation {
     ./0002-xwayland.patch
     ./0003-plugins-qpa-allow-using-nixos-wrapper.patch
     ./0001-NixOS-Unwrap-executable-name-for-.desktop-search.patch
+    # Pass special environments through arguemnts to `kwin_wayland`, bypassing
+    # ld.so(8) environment stripping due to `kwin_wayland`'s capabilities.
+    # We need this to have `TZDIR` correctly set for `plasmashell`, or
+    # everything related to timezone, like clock widgets, will be broken.
+    # https://invent.kde.org/plasma/kwin/-/merge_requests/1590
+    (fetchpatch {
+      url = "https://invent.kde.org/plasma/kwin/-/commit/9a008b223ad696db3bf5692750f2b74e578e08b8.diff";
+      sha256 = "sha256-f35G+g2MVABLDbAkCed3ZmtDWrzYn1rdD08mEx35j4k=";
+    })
   ];
   CXXFLAGS = [
     ''-DNIXPKGS_XWAYLAND=\"${lib.getBin xwayland}/bin/Xwayland\"''