If set to 'verbose' additional information will be printed.
<li>LIBGL_DRIVERS_PATH - colon-separated list of paths to search for DRI drivers
<li>LIBGL_ALWAYS_INDIRECT - forces an indirect rendering context/connection.
-<li>LIBGL_ALWAYS_SOFTWARE - if set, always use software rendering
+<li>LIBGL_ALWAYS_SOFTWARE - if set to `true`, always use software rendering
<li>LIBGL_NO_DRAWARRAYS - if set do not use DrawArrays GLX protocol (for debugging)
<li>LIBGL_SHOW_FPS - print framerate to stdout based on the number of glXSwapBuffers
calls per second.
Use kill -10 <pid> to toggle the hud as desired.
<li>GALLIUM_HUD_DUMP_DIR - specifies a directory for writing the displayed
hud values into files.
-<li>GALLIUM_DRIVER - useful in combination with LIBGL_ALWAYS_SOFTWARE=1 for
+<li>GALLIUM_DRIVER - useful in combination with LIBGL_ALWAYS_SOFTWARE=true for
choosing one of the software renderers "softpipe", "llvmpipe" or "swr".
<li>GALLIUM_LOG_FILE - specifies a file for logging all errors, warnings, etc.
rather than stderr.