Future of the pango dependency

See https://blogs.gnome.org/mclasen/2022/06/22/pango-1-90/

I am slowly getting ready to make a pango 2.0, so thinking through all the issues.

One of the more gnarly ones is that librsvg uses pango to render text ,and gets injected via a gdk-pixbuf module in all sorts of environments, including gtk 2, 3, and 4. Once GTK 5 appears, we will be in a situation where some of these environments link against pango 1.x, and some against pango 2. Those are not going to live peacefully together in the same process.

Possible solutions:

• Stop providing a gdk-pixbuf module, expect apps to link against librsvg if they want svg support
• Stop using pango in libsvg, use something else (maybe rust has cool text rendering crates ?)
• Stop linking against pango in librsvg, find all the necessary symbols at runtime via dlopen/dlsym

Federico, we should discuss this at Guadec.