Features from optional dependencies

gdk4 implicit feature

Enables gdk4 ^0.5.0

Glib-based dependencies, for rendering.

Affects papyri::render, papyri::ffi

gdk-pixbuf implicit feature

Enables gdk-pixbuf ^0.16.0

gdk-pixbuf:

Rust bindings for the GdkPixbuf library

Affects papyri::render, papyri::ffi

cairo-rs implicit feature

Enables cairo-rs ^0.16.1

cairo-rs:

Rust bindings for the Cairo library

Affects papyri::render, papyri::ffi