Many changes
- use musl cross compiler for x86_64 to ensure build environment is sane
- build musl libc, busybox, fsck and initd with the cross compiler
- e2fsprogs (used to build fsck) upgraded to 1.42.10
- mount efivars in initramfs and initscript
- ensure the temporary directory is removed in case of problem in mkinitramfs
- init system will not use perp anymore