suppress `-Wcast-function-type-strict` when casting to PyCFunction (#100068)
suppress `-Wcast-function-type-strict` when casting to PyCFunction
Summary:
These casts are a necessary evil due to the design of Python. Python
ultimately casts it back to the original type based on the flags
specified in the `PyMethodDef`.
Nevertheless, the new Clang flag `-Wcast-function-type-strict` breaks
with this.
While here, convert the cast to a `reinterpret_cast`.
Test Plan: Should be a no-op. Rely on CI.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/100068
Approved by: https://github.com/Skylion007
