testing/nyxt: upgrade to 2.2.4

Since I mentioned nyxt in my sbcl MR, I might as well try and see if it builds.

Most of the dependencies (glib-networking, gsettings-desktop-schemas, gstreamer) are actually dependencies of webkit2gtk, so I used that in the depends= line instead.

It also requires 2 patches (imported from Void Linux) that make it properly load libfixposix and libwebkit2gtk (for WebKit, it tried to load the unversioned library, which is only available in the -dev package; as for libfixposix, it didn't load it at all and went straight to complain about missing symbol lfp_errno).