Use GLib's i18n support instead of copying and pasting that
logic into its own header. This deprecates the vips/intl.h
header in favour of glib/gi18n.h.
You must now include vips7 support explicitly with
#include <vips/vips7compat.h>
in your code just after including `vips.h`.
The old vips7 names, such as `Rect`, were starting to cause problems
with other packages like opencv.
the vips7 loaders were a thin layer over the new VipsForeign system
however! VipsForeign does various "useful" things, like open via disc,
and this resulted in stuff like
vips im_jpeg2vips huge.jpg x.v
decompressing to a temp file before copying to x.v
im_jpeg2vips() and friends now call the low-level loaders directly and
avoid the extra mechanisms in VipsForeign
"nip2 huge.jpg" was loading twice as well, for the same reason