gh-98410: move getbufferproc and releasebufferproc to buffer.h by davidhewitt · Pull Request #31158 · python/cpython

Thanks for the catch!
Definitely suitable for merge. It won't make it to Python 3.11.0 (sorry!), but it can go in 3.12. (And possibly in 3.11.1, since it's only affecting API rather than ABI.)
Please move the definitions to Include/buffer.h, together with the other buffer API. That way you shouldn't need the forward definition.
Please add these to Misc/stable_abi.toml, as typedef entries added in 3.12, and re-run make regen-limited-abi.

Let me know if you want more info, or if you'd prefer to leave this to me.