The work would be based on meta-gir, but with the mandatory goal of producing patches of sufficient quality that can be sent upstream. The upstream tarball is a mess that mashes together several different things and was never designed for cross-compiling; and meta-gir is also difficult to understand: autotools-based build files are patched using undocumented patchfiles, then again patched from the recipe using sed, with sparse or absent comments - all that needs to be sorted. I'm looking into this now, but don't yet have anything to show.
Please check with upstream before putting much work into meta-gir. There seems to be an effort in place to fix gobject-introspection for cross-compile environment using the mesonbuild tool: https://blogs.gnome.org/ignatenko/2015/07/24/guadec-presentation-preview-compiling-gnome-apps-with-the-meson-build-system/ Someone needs to determine if this is actually going to happen and if it solves our x-compile problems.
This is the upstream discussion: https://bugzilla.gnome.org/show_bug.cgi?id=743280 What I take from it, it's not happening soon, and they're not replacing autotools with it in existing projects. In any case, I don't see how mesonbuild would fix g-o in cross-compile environments. The link you provide says nothing about that specifically. The issue with g-o isn't the build system, it's the g-o tools themselves that need to be compiled both for native and target architectures, and then require a delicate combination of both to produce correct output.
Oh well, the impression I had was that the next version of gnome might switch to mesonbuild and that mesonbuild would help with x-compile of the poorly designed g-object-introspection code. If that's not the case then I agree with proceed with your plan. Thanks for taking the time to investigate and reply.
No problem. I'm in the middle of making it all work, and hope to produce an initial patchset for testing and review in 5-10 working days.
Posted the initial patchset here http://lists.openembedded.org/pipermail/openembedded-core/2015-November/112455.html
Patches are in master!