arch+matlab: setup opengl rendering

hardware accelerated rendering needs enabling.

1. check out the arch-wiki page.
2. i needed to install the intel graphics driver. explained here.
3. to set the opengl paths (as explained in the wiki), i needed to modify the .desktop file
   1. for me, the path was: /usr/share/applications/matlab.desktop
   2. changed execution line
      1. before: Exec=matlab -desktop -nosplash
      2. after: Exec=/my/personal/binary/path/matlab_startWithEnvVars
   3. created seperate start script
      1. path: (same as given to Exec command above)
      2. content:
         [code language="bash" collapse="true" title="/my/personal/binary/path/matlab_startWithEnvVars"]
         #!/bin/sh

         export LD_PRELOAD=/usr/lib/libstdc++.so
         export LD_LIBRARY_PATH=/usr/lib/xorg/modules/dri/

         exec /usr/local/bin/matlab -desktop -nosplash "$@"
         [/code]

      3. make file executable