Can you link the code? Proc macros are not inherently slow to compile, but most proc macros pull in the `syn` and `quote` crates for convenience, which are fairly heavyweight (and then most people experience proc macros most commonly via Serde, which is doing a ton of work on its own). In simple cases you can forego most of that work, and some libraries like https://github.com/Manishearth/absolution exist as lightweight alternatives in these cases. Depending on what the Asahi driver needs it could also benefit from something like this (although without seeing the code I'm not sure why it would need proc macros when it sounds like conditional compilation via `cfg` would suffice there).