See https://github.com/rust-lang/rust/issues/120770

Part-of: <https://gitlab.gnome.org/GNOME/librsvg/-/merge_requests/927>

Fix and work around excessively strict dead_code lint in Rust 1.78 nightly

See merge request GNOME/librsvg!927

Simplifies the code a bit

Part-of: <https://gitlab.gnome.org/GNOME/librsvg/-/merge_requests/926>

librsvg-c: Use glib::Properties macro

See merge request GNOME/librsvg!926

Part-of: <https://gitlab.gnome.org/GNOME/librsvg/-/merge_requests/928>

See:

- https://github.com/rust-lang/rust/issues/121362
- https://github.com/rust-lang/rust/issues/121312
- https://github.com/rust-lang/rust/issues/120770

Part-of: <https://gitlab.gnome.org/GNOME/librsvg/-/merge_requests/928>

ci: Add cargo-c as a dependency

See merge request GNOME/librsvg!928

Image-rs is happy to return images with dimensions of zero - in the
example image in this bug, it returns a 1*0 image.  Relax the
assertion, which was valid in the gdk-pixbuf days, and return an
error instead.

https://gitlab.gnome.org/GNOME/librsvg/-/issues/1060

The feOffset implemenetation doesn't need integer bounds; we can
actually use floating-point bounds to make Cairo clip at sub-pixel
positions.

This commit has regenerated versions of two test files that use
feOffset, since now it does not clip at exact pixel boundaries.

Fixes https://gitlab.gnome.org/GNOME/librsvg/-/issues/1059

Fix two panics found by fuzzing

See merge request GNOME/librsvg!941

Prepare 2.57.92

See merge request GNOME/librsvg!944