surfaceflinger: Add BOARD_NO_RGBX_8888 option

Current GL libraries shipped with Froyo do not correctly support this.
Google added this option specifically for Droid, but it is applicable to
other devices with older userspace.

Change-Id: Ied682a17b2820b58a2a240f975390ddcc11b7815

services/surfaceflinger/Android.mk

@@ -23,6 +23,9 @@ LOCAL_CFLAGS += -DGL_GLEXT_PROTOTYPES -DEGL_EGLEXT_PROTOTYPES
 ifeq ($(TARGET_BOARD_PLATFORM), omap3)
 	LOCAL_CFLAGS += -DNO_RGBX_8888
 endif
+ifeq ($(BOARD_NO_RGBX_8888), true)
+	LOCAL_CFLAGS += -DNO_RGBX_8888
+endif
 ifeq ($(TARGET_BOARD_PLATFORM), s5pc110)
 	LOCAL_CFLAGS += -DHAS_CONTEXT_PRIORITY
 endif