There is a new pull request by icp1994 against master on the void-packages repository

https://github.com/icp1994/void-packages egrep
https://github.com/void-linux/void-packages/pull/41593

chroot-grep: patch out problematic warnings in egrep and fgrep.
This mirrors the changes from grep in https://github.com/void-linux/void-packages/commit/ef5ffe4d696b31041c272be92e912fb454c075ac into chroot-grep.

A patch file from https://github.com/void-linux/void-packages/pull/41593.patch is attached