Show 'Required By' in -Sii output

Just as we do in -Qi, we can compute required by information for sync
database packages. The behavior seems sane; for a given package, the -Sii
required by will show all packages in *any* sync database that require it.

Implements FS#16244.

Signed-off-by: Dan McGee <dan@archlinux.org>

0 files changed, 0 insertions, 0 deletions