Available features does not respect basedir

Was trying to generate an initramfs from the Alpine live CD to fix a nonbooting system. Couldn't get it to generate a correct initramfs with all the modules that I needed, because sysconfdir is hardcoded to /etc/mkinitfs regardless of what is passed in -b, and I don't think there's any way to override it.

You can test this by mounting an Alpine rootfs to /mnt, adding a feature to /mnt/etc/mkinitfs/features.d that isn't there in /etc/mkinitfs/features.d, and then running mkinitfs -b /mnt -L.