It's quite useful to be able to see what we are going to build, esp. as the...

It's quite useful to be able to see what we are going to build, esp. as the i965 driver is not enabled by default. Obviously the summary can be extended with extra information.
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>

configure.ac

@@ -175,3 +175,25 @@ AC_OUTPUT([
 	libva-tpi.pc
 ])
 
+# Print a small summary
+
+echo ""
+echo "libva - ${LIBVA_VERSION}"
+echo ""
+
+echo "  Global :"
+echo "     Prefix: ${prefix}"
+echo ""
+
+AS_IF([test x$enable_i965_driver = xyes], [DRIVERS="i965 $DRIVERS"]) 
+AS_IF([test x$enable_dummy_driver = xyes], [DRIVERS="dummy $DRIVERS"])
+
+echo "  Drivers: ${DRIVERS}"
+
+AS_IF([test x$USE_GLX = xyes], [BACKENDS="glx $BACKENDS"])
+BACKENDS="x11 $BACKENDS"
+AS_IF([test x$enable_dummy_backend = xyes], [BACKENDS="dummy 
+$BACKENDS"])
+
+echo "  Winsys : ${BACKENDS}"
+