cell: asst build fixes in linux-cell config

Add -D_SVID_SOURCE to silence warnings when building glx files.
Don't build the non-gallium drivers.

configs/linux-cell

@@ -28,13 +28,16 @@ SDK = /opt/cell/sdk/usr
 CFLAGS = $(OPT_FLAGS) -Wall -Winline -Wmissing-prototypes \
 	-fPIC -m32 -std=c99 -mabi=altivec -maltivec \
 	-I. -I$(SDK)/include \
-	-DGALLIUM_CELL -DUSE_XSHM -D_BSD_SOURCE
+	-DGALLIUM_CELL -DUSE_XSHM -D_BSD_SOURCE -D_SVID_SOURCE
 
 CXXFLAGS = $(CFLAGS)
 
 # Omitting glw here:
 SRC_DIRS = gallium mesa gallium/winsys glu glut/glx glew
 
+# Build no traditional Mesa drivers:
+DRIVER_DIRS =
+
 
 MKDEP_OPTIONS = -fdepend -Y