Introduces a new USEKERNCONFNAME, that works as follows:
- if USEKERNCONFNAME is undefined, then nothing is changed;
- if USEKERNCONFNAME is defined, then install all kernels in a directory named exactly as the kernel configuration.
For example, if KERNCONF = GENERIC CURRENT STABLE, then the 3 kernels would be installed in /boot/GENERIC, /boot/CURRENT, /boot/STABLE respectively. No /boot/kernel would be created.
Then, /boot/loader.conf should be updated with the new default kernel name (by setting the "kernel" variable) or a /boot/kernel file should be created manually (by copying a valid kernel directory, by soft linking to a valid kernel directory...).