Bug#811195: Check for OpenGL 2.0 and enable QT_XCB_FORCE_SOFTWARE_OPENGL if not found

[Lisandro Damián Nicanor Pérez Meyer <lisandro@debian.org>]

Source: qtbase-opensource-src
Version: 5.5.1+dfsg-12
Severity: normal

Long story: <http://lists.qt-project.org/pipermail/development/2016-January/024336.html>

We need to decied where this should reside. I think it should come along with
XCB's QPA plugin, but it will be part of libqt5gui5 soon.

-- System Information:
Debian Release: stretch/sid
  APT prefers unstable
  APT policy: (990, 'unstable'), (500, 'unstable-debug'), (500, 'buildd-unstable'), (500, 'testing')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.3.0-1-amd64 (SMP w/2 CPU cores)
Locale: LANG=es_AR.UTF-8, LC_CTYPE=es_AR.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash
Init: systemd (via /run/systemd/system)