EFI suport for utils/write-hd-image-squash.sh: new packages (syslinux6, nasm, mtools, gnu-efi-libs)
add non-https mirror for pciutils, fix i386 build
enable (U)EFI-related options in kernel config
add dosfstools package since we now use fat filesystem also
use sabotage cpio and mkfs.vfat to minimize external dependencies