Bug#1116553: valac: not Multi-Arch co-installable due to inclusion of unprefixed vala-gen-introspect

[Helmut Grohne]

Hi Simon,

On Sun, Sep 28, 2025 at 03:43:12PM +0100, Simon McVittie wrote:
> It is not possible to install (for example) valac:amd64 and valac:i386 
> at the same time, because both packages contain the vala-gen-introspect 
> script, with different contents. This is undesirable when trying to make 
> cross-compiling work, because it means all experiments have to be done 
> in a chroot/container that has valac:${host} but not valac:${build}.

Thank you for working on this.

> Perhaps we could have a Debian-specific patch to make 
> vala-gen-introspect Multi-Arch co-installable, by teaching it to run 
> ${PKG_CONFIG-pkg-config} instead of pkg-config, and setting:
> 
>     libdir=$(${PKG_CONFIG-pkg-config} --variable=libdir glib-2.0)
> 
> since valac already Depends on libglib2.0-dev?
> 
> This is not perfect, since it assumes that $PKG_CONFIG is set whenever 
> cross-compiling, but that seems adequate for a component that is already 
> deprecated.

I agree that this is a compromise worth trying. The need to export
PKG_CONFIG is not universal, but e.g. in the Perl ecosystem we
occasionally face it as well. The failure mode (of failing to export
PKG_CONFIG) is not very obvious, but to me the deprecation is a strong
reason to do this anyway.

Helmut