Log Message:
graphics/libheif: import libheif-1.8.0

libheif is an ISO/IEC 23008-12:2017 HEIF and AVIF (AV1 Image File
Format) file format decoder and encoder.

HEIF and AVIF are new image file formats employing HEVC (h.265) or
AV1 image coding, respectively, for the best compression ratios
currently possible.

libheif makes use of libde265 for HEIF image decoding and x265 for
encoding.  For AVIF, libaom is used as encoder and decoder.
Alternative codecs for, e.g., AVC and JPEG can be provided as
plugins.