Library for handling .avif files (utilities)

 This library aims to be a friendly, portable C implementation of the AV1
 Image File Format as described in https://aomediacodec.github.io/av1-avif/.
 .
 This package provides several utilities provided by the library:
  - avifdec
  - avifenc
 .
 Due to the temporary lack of support libraries, no decoder is available
 for now. As a result, the avifenc binary won't work.