Depth texture shadows break untextured rendering

[Philip]

Using x11-drivers/xf86-video-intel-2.12.0, media-libs/mesa-7.8.2, Intel GMA 4500MHD:

When shadows are enabled at startup, untextured things (flat colours in GUI, and unit selection circles) render incorrectly (black in GUI, invisible or mostly-terrain-coloured selection circles). This seems to happen regardless of whether shadows are enabled or disabled at runtime via the menu. This doesn't seem to happen if shadows are disabled by default, then enabled at runtime. This doesn't seem to happen when running with LIBGL_ALWAYS_INDIRECT - not sure if that indicates it's a driver bug.