New review comment by gbrlsnchs on void-packages repository

https://github.com/void-linux/void-packages/pull/23623#discussion_r468287563

Comment:
Because the Cargo build style [sets it when nothing is set](https://github.com/void-linux/void-packages/blob/5474e8770623edc15f2c552e2beae77f86e729d8/common/build-style/cargo.sh#L20). If the build style didn't set it, it would just work, but since it sets it to `.`, I have to override it, otherwise the package won't compile.