fix: Avoid integer overflows in function `png_xy_from_XYZ`

This is a cherry-picked of commit f45531cc141dc20dc7a4046bbe92270b1e799a5d
from branch 'libpng18'.

Reviewed-by: Cosmin Truta <ctruta@gmail.com>
Signed-off-by: John Bowler <jbowler@acm.org>
Signed-off-by: Cosmin Truta <ctruta@gmail.com>
1 file changed