gallium: Introduce new subdirs build variables

(based on gallium-xorg-driver/commit 270ce504052d415870a25ab59818b2309eb8ac13)
diff --git a/configs/default b/configs/default
index 13bda58..3a49c5a 100644
--- a/configs/default
+++ b/configs/default
@@ -89,11 +89,14 @@
 EGL_DRIVERS_DIRS = demo
 
 # Gallium directories and 
+GALLIUM_DIRS = auxiliary drivers state_trackers
 GALLIUM_AUXILIARY_DIRS = draw translate cso_cache pipebuffer tgsi sct rtasm util indices
 GALLIUM_AUXILIARIES = $(foreach DIR,$(GALLIUM_AUXILIARY_DIRS),$(TOP)/src/gallium/auxiliary/$(DIR)/lib$(DIR).a)
 GALLIUM_DRIVER_DIRS = softpipe i915simple i965simple nv04 nv10 nv20 nv30 nv40 nv50 failover trace
 GALLIUM_DRIVERS = $(foreach DIR,$(GALLIUM_DRIVER_DIRS),$(TOP)/src/gallium/drivers/$(DIR)/lib$(DIR).a)
 GALLIUM_WINSYS_DIRS = xlib egl_xlib
+GALLIUM_WINSYS_DRM_DIRS =
+GALLIUM_STATE_TRACKERS_DIRS = glx
 
 
 # Library dependencies