* hw/kdrive/ephyr/ephyrdriext.c: added this to implement a DRI extension
into Xephyr. Normally the DRI extension is only present in the
xfree86 server, but I have ported it to Xephyr. The extension calls
functions that declared/defined in ephyrdri.h ephyrdri.c that
forwards the DRI calls to the host X. It does not work yet, as this
entry is just to put the big bricks in place.
* hw/kdrive/ephyr/ephyrdri.c,h: declaration & definition of the
DRI client API that would hit the hostX server.
* hw/kdrive/ephyr/GL/internal/dri_interface.h: added this, otherwise
inclusion of /usr/include/X11/dri/xf86dri.h won't compile