New comment by Duncaen on void-packages repository

https://github.com/void-linux/void-packages/pull/46165#issuecomment-1730076889

Comment:
We generally don't test for values of those environment variables and instead check if they are set or not, that makes the code easier and avoids having to define what yes/no/true/false/0/1 is the correct choice.

Not sure why you would only sign `vmlinuz` kernels and ignore `vmlinux`.