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

https://github.com/yopito/void-packages memtest.5.31b
https://github.com/void-linux/void-packages/pull/21179

[WIP] memtest86+: update to 5.31b
* not a stable release
* build fine from x86_64/musl
* run fine on my i5-5300U CPU @ 2.30GHz, 8GB RAM, both fail-safe and SMP modes
* glitches on % calculations (test #8 advancement, overall is 100% on hitting test 8/11)

A patch file from https://github.com/void-linux/void-packages/pull/21179.patch is attached