Avif support / libheiff.so is missing in latest release

[francm]

Since version 8.10.2-a7234b1, the binary release is provided without libheiff.so, so AVIF generation fails with an error.

com.criteo.vips.VipsException: Unable to write image buffer
 vips error buffer contains: VipsOperation: class "heifsave_buffer" not found

The source of the problem could be https://github.com/criteo/JVips/pull/88

[klh]

+1 on this

[klh]

@dbouron