Please put the ::Error class in a real namespace or rename it something like "::HeifError"

[danhd123]

"Error" is a very big claim in the "::" namespace, and it conflicts at link time with other libraries, some of which (eg Helix's Perforce API) are effectively un-recompilable. While it's not fair that libheif should be the one to fix this particular conflict, no library should be polluting the :: namespace like this anyway.

I have had to remove heif support from my static ImageMagick build (which likely means even more work later) because of this.