New review comment by Duncaen on void-packages repository

https://github.com/void-linux/void-packages/pull/24400#discussion_r483828804

Comment:
This shouldn't be necessary, the cmake build_style already sets up the build directory at configure time before pre_build.
https://github.com/void-linux/void-packages/blob/master/common/build-style/cmake.sh#L6