qcow1: Make padding in the header explicit We were relying on all compilers inserting the same padding in the header struct that is used for the on-disk format. Let's not do that. Mark the struct as packed and insert an explicit padding field for compatibility. Cc: qemu-stable@nongnu.org Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>