openshadinglanguage: explicitly disable Qt to avoid warnings

Otherwise build logs have some scary red output about it missing.

pkgs/by-name/op/openshadinglanguage/package.nix

@@ -32,6 +32,8 @@ stdenv.mkDerivation (finalAttrs: {
   };
 
   cmakeFlags = [
+    (lib.cmakeBool "USE_QT" false)
+
     # Build system implies llvm-config and llvm-as are in the same directory.
     # Override defaults.
     (lib.cmakeFeature "LLVM_BC_GENERATOR" "${clang}/bin/clang++")