* commit 'f5d46d33':
  vmnc: check that subrectangles fit into their containing rectangles

See 6ba02602

This merge keeps our condition against w-i and h-j instead of bw and bh.
One may be more correct than the other, but I'm keeping our behaviour
here for safety reasons.

The style and formatting is merged.
Merged-by: Clément Bœsch <u@pkh.me>