swift

fe335472 - [AutoDiff] Use `@derivative` attribute to register tgmath derivatives.

[AutoDiff] Use `@derivative` attribute to register tgmath derivatives. - Compile stdlib with `-enable-experimental-cross-file-derivative-registration`. - This is necessary for using `@derivative` with tgmath functions, since some original functions (e.g. the `tan(_: Double) -> Double`) are imported from Clang. - Fix `@derivative` attribute SILGen for foreign original declarations. - Replace `@differentiable(jvp:vjp)` with `@derivative` for tgmath functions. Resolves TF-1087: `@derivative` attribute SILGen crash foreign declarations. Progress towards TF-1085: using `@derivative` attribute in the stdlib.