* common/iobuf.c (iobuf_get_filelength): Change return type to
uint64_t and remove the overflow args.  For Windows always use
GetFileSizeEx which is available since the long EOL-ed Windows XP.
* g10/sign.c (write_plaintext_packet): Adjust for changed
iobuf_get_filelength.
* g10/encrypt.c (encrypt_simple, encrypt_crypt): Ditto.
* g10/photoid.c (generate_photo_id): Ditto.  Also add an upper limit.
* g10/filter.h (progress_filter_context_t): Change amount values to
use uint64_t.
* g10/progress.c (write_status_progress): Change accordingly.