Allow specifying derive name

[spease]

There's probably some overlap with this and other issues, but rather than having a derive() function for each derive, I'd just either let somebody specify it (derive("PartialOrd")) or specify multiple ones somehow (derive("Clone,Copy")). This reduces the API size and increases functionality.

There are some special cases where derivations automatically trigger other derivations, I'd either just make derive() a straight specification of exactly what you want to appear (this might allow for other things besides just names down the road, if that ever gets supported). Or go ahead and parse the list and automatically derive those things.

[emilio]

The issue with this is that different derive(..) stuff have different requirements. Those requirements are encoded in src/ir/analysis/derive_*. Not sure how feasible would it be to make that logic work for generic derive, I guess someone would have to try.

[spease]

I was suggesting hardcoding the the requirements for the default derives. Presumably user libraries are not going to replace them, or at least not commonly.

[pvdrz]

you can use the custom derive API for this nowadays

[Plegeus]

you can use the custom derive API for this nowadays

Dear Pvdrz,
Could you give me a pointer to this api?
I have been looking for this four an hour now, all I see is the specific function (derive_copy, derive_debug, etc.) on the Builder struct.
Thank you.

[pvdrz]

https://docs.rs/bindgen/latest/bindgen/callbacks/trait.ParseCallbacks.html#method.add_derives