This introduces support for dd-style progress reporting on POSIX
systems, if the user hasn't specified -p to report progress. If sent a
SIGUSR1, qemu-img will report current progress for commands that
support progress reporting.
Signed-off-by: NJes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>