kdeApplications.print-manager: fix build

Just a quick and not pleasant fix until we update
kdeApplications. And that needs to be done very soon.

pkgs/applications/kde/print-manager.nix

@@ -20,4 +20,10 @@ mkDerivation {
     kwidgetsaddons kitemviews kio kwindowsystem plasma-framework qtdeclarative
   ];
   outputs = [ "out" "dev" ];
+  # Fix build with cups deprecations etc.
+  # See: https://github.com/NixOS/nixpkgs/issues/73334
+  NIX_CFLAGS_COMPILE = [
+    "-Wno-error=deprecated-declarations"
+    "-Wno-error=format-security"
+  ];
 }