gnome-base/librsvg: workaroud/fix tests w/ libxml2-2.15.0

The patch used is from nixpkgs. It only touches tests and still expects
an error, just not exactly the same error as before, so it's good enough
as a workaround for us for now.

Closes: https://bugs.gentoo.org/964256
Signed-off-by: Sam James <sam@gentoo.org>

gnome-base/librsvg/files/librsvg-2.60.0-libxml2-2.15.0-tests.patch

@@ -0,0 +1,28 @@
+https://bugs.gentoo.org/964256
+https://gitlab.gnome.org/GNOME/librsvg/-/issues/1201
+
+"This patch makes the test succeed. Therefore, there is probably not a security issue here.
+An error does occur, it just is not being reported as TooManyLoadedElements.
+So just the dumb thing, adding an unwrap and expecting it to fail is a decent enough bandaid."
+--- a/rsvg/tests/errors.rs
++++ b/rsvg/tests/errors.rs
+@@ -14,15 +14,12 @@ use rsvg::{CairoRenderer, ImplementationLimit, Loader, LoadingError, RenderingEr
+ 
+ #[ignore]
+ #[test]
++#[should_panic]
+ fn too_many_elements() {
+     let name = "tests/fixtures/errors/bug515-too-many-elements.svgz";
+ 
+-    assert!(matches!(
+-        Loader::new().read_path(name),
+-        Err(LoadingError::LimitExceeded(
+-            ImplementationLimit::TooManyLoadedElements
+-        ))
+-    ));
++    // libxml2 might return an error without updating the element count, so just expect any error, not specifically too many elements
++    Loader::new().read_path(name).unwrap();
+ }
+ 
+ fn rendering_instancing_limit(name: &str) {
+

gnome-base/librsvg/librsvg-2.60.0.ebuild

@@ -62,6 +62,10 @@ QA_FLAGS_IGNORED="
 	usr/lib.*/gdk-pixbuf*/*/loaders/*
 "
 
+PATCHES=(
+	"${FILESDIR}"/${PN}-2.60.0-libxml2-2.15.0-tests.patch
+)
+
 pkg_setup() {
 	rust_pkg_setup
 	python-any-r1_pkg_setup