- Let's just have one header definining export- and visibility-
macros for Calamares. They are still selected based on the
export flags (*_PRO), just defined in one header instead of two.
- The mitigations are slightly intrusive, and may clash
with other, similar mitigations (especially for initramfs,
the recommended solution is to configure the system with
the snippet outside of Calamares).
- new implementation handles blank (maps to "all") configuration,
- allows specifying "$uname" as kernel name, to use `uname -r`,
- allows specifying a specific kernel.
