[PATCH buildbot] docker,worker: install g++-multilib

[Alois Klink]

>From [openwrt/docker at 5484951][1] (GitHub PR [#89][2]):

Node fails to cross-compile from a 64-bit build machine to 32-bit host
with the following error:

```
  In file included from /usr/include/c++/8/memory:62,
  from ../deps/v8/src/libplatform/default-foreground-task-runner.h:8,
  from ../deps/v8/src/libplatform/default-foreground-task-runner.cc:5:
  /usr/include/c++/8/bits/stl_algobase.h:59:10: fatal error: bits/c++config.h:
    No such file or directory
  #include <bits/c++config.h>
          ^~~~~~~~~~~~~~~~~~
  compilation terminated.
```

On Debian, `g++-multilib` can be installed to fix this.

[1]: https://gitlab.com/openwrt/docker/-/commit/54849510d7802028b94757051cca6d004a9ca1d1
[2]: https://github.com/openwrt/docker/pull/89

Fixes: https://github.com/openwrt/packages/issues/18476
Fixes: https://forum.openwrt.org/t/142722
Signed-off-by: Alois Klink <alois at aloisklink.com>
---

Notes:
    I've made a merge request on `openwrt/buildbot` GitLab too, see
    <https://gitlab.com/openwrt/buildbot/-/merge_requests/11>,
    but @hnyman on the OpenWRT forums recommended me to cross-post
    it to mailing list since GitLab isn't well used.

    (apologies if any formatting is wrong in this, it's my first time
     using `git send-email`)

    As of `Tue Nov 22 23:02:34 2022`, you can view
    https://downloads.openwrt.org/releases/faillogs-22.03/arm_cortex-a9_vfpv3-d16/packages/node/compile.txt
    and see the above error
    (I'm assuming that this buildbot is creating the above errors).

    We should probably also note in the OpenWRT wiki in
    https://openwrt.org/docs/guide-developer/toolchain/install-buildsystem#package_prerequisites
    that `node` requires `g++-multilib`.

    These changes are untested, but they're pretty simple so should work.
    The GitLab repo has some CI as well, but it doesn't seem to be working
    since my merge request is from a forked repo.

 docker/buildworker/Dockerfile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/docker/buildworker/Dockerfile b/docker/buildworker/Dockerfile
index 5219f92..871b7b1 100644
--- a/docker/buildworker/Dockerfile
+++ b/docker/buildworker/Dockerfile
@@ -18,6 +18,7 @@ RUN \
 		ccache \
 		curl \
 		gawk \
+		g++-multilib \
 		gcc-multilib \
 		genisoimage \
 		git-core \
--
2.34.1