There's a merged pull request on the void-packages repository

qmk: change dependency to cross-arm-none-eabi
https://github.com/void-linux/void-packages/pull/22370

Description:
cross-arm-none-eabi pulls in both cross-arm-none-eabi-gcc and
cross-arm-none-eabi-newlib, and I found out the latter is also needed to build
at least planck/rev6 firmware, and likely other keyboards with ARM based
controllers.

Found out with help from Discord users @Erovia and @fauxpark on the qmk server.

Using cross-arm-none-eabi as dep to get -newlib suggested by @ericonr.