for TIFF predictor hotfix

bump version for animated webp load fix

allow spng.pc and libspng.ps for libspng discovery

note HEIC fix in changelog

see libvips#1921

fix build with libheif save buit not load

We had some definitions inside the #ifdef HEIFLOAD.

Thanks estepnv

libvips#1844

note render thread change in changelog

fix write ICC profile to webp

ooops, a typo broke ICC profile write to webp 18 days ago

thanks augustocdias

see libvips#1767

Merge pull request libvips#1756 from libvips/heif-workaround

try to work around some broken heic images

Merge branch 'master' of github.com:libvips/libvips

add LT_INIT