• Gnome-based and other applications report messages like “Failed to initialize gtk+: Unable to initialize the Clutter backend: no available drivers found.”
• glxinfo reports GLX Version is 1.2
• Disabling GLX entirely in /etc/x2go/x2goagent.options via -extension GLX does not work because the application does not have the capability to work without GLX at all.

Use a wrapper/proxy library provided by Mesa. The applications will use the supplied libGL.so, which in turn uses the lib interface to talk to the X server (nxagent) rather than the GLX interface. From the applications' perspective, they have GLX 1.4.

(with trusty-updates mesa 10.1.3-0ubuntu0.3)

sudo aptitude build-dep mesa
sudo aptitude install scons llvm-dev
apt-get source mesa
cd mesa
scons libgl-xlib
export LD_LIBRARY_PATH=`pwd`/build/linux-x86_64-debug/gallium/targets/libgl-xlib/:${LD_LIBRARY_PATH}
glxinfo | grep 'GLX version:'

Ensure that some required tools are installed:

emerge -1av app-portage/gentoolkit dev-util/scons dev-python/mako

Create a place to store the library - adapt this path to your liking.

mkdir -p /usr/local/share/mesa-libgl-xlib

Place the following line in a suitable place - either in your .bashrc or in the script that calls the individual application:

export LD_LIBRARY_PATH=/usr/local/share/mesa-libgl-xlib/:${LD_LIBRARY_PATH}

Configure portage to keep the working area that is used to compile the Mesa package. Before doing so, ensure that the USE flags for media-libs/mesa are configured to your liking.

export MESA_VERSION=$(equery -q list media-libs/mesa -F '$version')
ebuild "/usr/portage/media-libs/mesa/mesa-${MESA_VERSION}.ebuild" prepare

Now compile the library and move it over to the storage location:

cd /var/tmp/portage/media-libs/mesa-${MESA_VERSION}/work/mesa-${MESA_VERSION}
scons libgl-xlib
cp build/linux-x86_64-debug/gallium/targets/libgl-xlib/* /usr/local/share/mesa-libgl-xlib/

Cleanup:

ebuild /usr/portage/media-libs/mesa/mesa-${MESA_VERSION}.ebuild clean