Bug#1061107: vapigen: Make it possible to cross-compile libraries with Vala bindings

[Simon McVittie]

On Thu, 18 Jan 2024 at 12:54:45 +0000, Simon McVittie wrote:
> Ideally, during a cross-build, we would like to run a build-architecture
> vapigen binary, but configure it (perhaps via command-line options or
> environment variables) so that it will find host-architecture GIR XML
> in /usr/lib/${DEB_HOST_MULTIARCH}/gir-1.0. The search paths need to
> be architecture-specific in order to find GLib-2.0.gir without having
> libgirepository1.0-dev installed, because libgirepository1.0-dev
> is not cross-compile-friendly. I don't think there are any other
> architecture-dependent paths involved, but the Vala maintainers would
> know what this tool does better than I do.
> 
> As a proof-of-concept, I was able to work around this in libportal by
> generating some local wrappers and overrides; but ideally this would
> be something that could be done centrally, with most of the work in the
> vala package.
> 
> I'll follow up with more concrete suggestions, but I wanted to open the
> bug with a relatively solution-neutral problem statement rather than
> jumping directly to a solution.

https://salsa.debian.org/gnome-team/vala/-/merge_requests/3 is an
implementation of what I had in mind.

https://salsa.debian.org/gnome-team/gcr4/-/merge_requests/2 is an example
of the matching change in a library that depends on vapigen.

(Salsa seems to be having some trouble right now, so you might need to
`git fetch` my branches and inspect them locally.)

    smcv