kitty: depend on wayland-scanner

Otherwise, wayland-scanner would be picked up from the wayland in
buildInputs, which isn't cross-friendly and will stop working when we
split wayland-scanner into a separate package.

pkgs/applications/terminal-emulators/kitty/default.nix

@@ -15,6 +15,7 @@
 , UserNotifications
 , libcanberra
 , libicns
+, wayland-scanner
 , libpng
 , python3
 , zlib
@@ -84,8 +85,12 @@ buildPythonApplication rec {
   ] ++ lib.optionals stdenv.isDarwin [
     imagemagick
     libicns  # For the png2icns tool.
+  ] ++ lib.optionals stdenv.isLinux [
+    wayland-scanner
   ];
 
+  depsBuildBuild = [ pkg-config ];
+
   outputs = [ "out" "terminfo" "shell_integration" "kitten" ];
 
   patches = [