There is a new pull request by tornaria against master on the void-packages repository

https://github.com/tornaria/void-packages mpir
https://github.com/void-linux/void-packages/pull/32693

mpir: fix update-check
This fixes site so that update-check works. No update available at this time.

A patch file from https://github.com/void-linux/void-packages/pull/32693.patch is attached