Describe the feature and motivation

OpenCV supports using libspng as an alternative png decoder in 4.7.0. However, OpenCV only supports building libspng from source but using pre-installed one by package manager like libpng. What I want is FindSPNG and only build from source if not found.

Motivation: ArchLinux included libspng in official repository. https://archlinux.org/packages/extra/x86_64/libspng/

Additional context

No response