nixgl: forward override calls to wrapped package

modules/misc/nixgl.nix

@@ -240,7 +240,15 @@ in {
 
             shopt -u nullglob # Revert nullglob back to its normal default state
           '';
-        }));
+        })) // {
+          # When the nixGL-wrapped package is given to a HM module, the module
+          # might want to override the package arguments, but our wrapper
+          # wouldn't know what to do with them. So, we rewrite the override
+          # function to instead forward the arguments to the package's own
+          # override function.
+          override = args:
+            makePackageWrapper vendor environment (pkg.override args);
+        };
 
     wrappers = {
       mesa = makePackageWrapper "Intel" { };