mesa cross-import fails

[Peter Pearse]

Binary package hint: xdeb

xdeb -a armel -d ../dest mesa
produces the armel binary packages, then fails whilst crossing them.

Attached the xdeb out put after the armel binaries are built & packages
[xdeb patched to output the failing command]

Attached the dpkg-cross command which returns failure when spawned.
It appears that dpkg-cross returns failure when any packages are skipped,
and that xdeb does not cope with this.

Note that the mesa code has to be patched as with the attached patch to reach this point.
The patch ensures host, rather than just built target, tools are using for compiling shaders.

[Peter Pearse (peter-pearse)]

Patch ensures host, as well as target, tools are built, and that the host tools are used during the build.

[Loïc Minier (lool)]

Peter, xdeb could easily call dpkg-cross in a way which doesn't fail on empty packages, but we actually want to cover these in the heuristics matching packages so that we know that the package is a host package, not a target package as it might appear in build-deps.

[Loïc Minier (lool)]

dpkg-cross: package libgl1-mesa-dri-experimental doesn't provide any useful files. Skipping.
dpkg-cross: package libgl1-mesa-glx doesn't provide any useful files. Skipping.
dpkg-cross: package libegl1-mesa-drivers-kms doesn't provide any useful files. Skipping.

dpkg-cross: package libegl1-mesa-drivers-x11 doesn't provide any useful files. Skipping.

This should probably be listed in the plugins section of the blacklist after reviewing the contents.

[Loïc Minier (lool)]

libgl1-mesa-dri-experimental is definitely a plugins package.

But libgl1-mesa-glx is not: it ships usr/lib/mesa/libGL.so.1.2 and usr/lib/mesa/libGL.so.1, and a ld.so.conf snippet (which I guess adds usr/lib/mesa to the search path).

libegl1-mesa-drivers-kms and libegl1-mesa-drivers-x11 are definitely of the plugin variety too.

So we need a way to dpkg-cross some GL lib into the cross-dir (usr/$triplet/lib) or we wont be able to link to -lGL.

[Steve Langasek (vorlon)]

whoops, sorry - was thinking this was a bug against mesa; we should of course still try to fix this for this cycle if it's an xdeb bug.

[Steve Langasek (vorlon)]

Well, xdeb relies on dpkg-cross for the actual crossing, so I guess that's the right package to fix this in.

Note that this is an Ubuntu-specific issue, as the mesa package in Ubuntu diverges from the Debian one in the use of this subdirectory + ld.so.conf dpkg alternative. The trivial thing for dpkg-cross to do is to special-case the contents of /usr/lib/mesa and map them to /usr/<arch>/lib.