[regression] Mir EGL clients all crash with SIGSEGV in XGetXCBConnection()

Running today's daily ISO, enabled universe and installed:

    $ sudo apt install miral-examples mir-graphics-drivers-desktop qterminal qtubuntu-desktop

Then,

    $ miral-app -launcher qterminal

works.

But after doing,

    $ sudo apt upgrade -y

It crashes as seen here.

Probably related:

    $ sudo apt install mir-demos
    $ mir_demo_server --test-client mir_demo_client_eglplasma

also crashes.

Avoiding EGL use by:

    $ miral-app -kiosk

Works until an EGL app is started

ProblemType: Crash
DistroRelease: Ubuntu 17.10
Package: miral-examples 1.3.2+17.04.20170330.5-0ubuntu1
ProcVersionSignature: Ubuntu 4.10.0-22.24-generic 4.10.15
Uname: Linux 4.10.0-22-generic x86_64
ApportVersion: 2.20.5-0ubuntu4
Architecture: amd64
CasperVersion: 1.383
CurrentDesktop: GNOME
Date: Thu Jun 8 16:15:14 2017
ExecutablePath: /usr/bin/miral-shell
LiveMediaBuild: Ubuntu 17.10 "Artful Aardvark" - Alpha amd64 (20170607)
ProcCmdline: /usr/bin/miral-shell --file /run/user/999/miral_socket --desktop_file_hint=miral-shell.desktop
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
Signal: 11
SourcePackage: miral
StacktraceTop:
 XGetXCBConnection () from /usr/lib/x86_64-linux-gnu/libX11-xcb.so.1
 ?? () from /usr/lib/x86_64-linux-gnu/mesa-egl/libEGL.so.1
 ?? () from /usr/lib/x86_64-linux-gnu/mesa-egl/libEGL.so.1
 ?? () from /usr/lib/x86_64-linux-gnu/mesa-egl/libEGL.so.1
 ?? () from /usr/lib/x86_64-linux-gnu/mesa-egl/libEGL.so.1
Title: miral-shell crashed with SIGSEGV in XGetXCBConnection()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo