Import libhevc

[Breakkk]

Hi, Have anyone imported libhevc into libheif? I try to add libhevc plugin, but can't decode success.

And I write the hevc data which libheif extracted from .heic file to local file. Both libde265 and libhevc can't decode it. Using nokia/heif extract hevc data from .heic can be decoded success. The difference between nokia/heif's hevc data and libheif's hevc data just have 16 bytes differ.