Add build flag for custom graphics
diff --git a/minuitwrp/Android.mk b/minuitwrp/Android.mk
index e86c77e..f0c7089 100644
--- a/minuitwrp/Android.mk
+++ b/minuitwrp/Android.mk
@@ -1,7 +1,13 @@
 LOCAL_PATH := $(call my-dir)
 include $(CLEAR_VARS)
 
-LOCAL_SRC_FILES := events.c resources.c graphics.c
+LOCAL_SRC_FILES := events.c resources.c
+
+ifneq ($(TW_BOARD_CUSTOM_GRAPHICS),)
+    LOCAL_SRC_FILES += $(TW_BOARD_CUSTOM_GRAPHICS)
+else
+    LOCAL_SRC_FILES += graphics.c
+endif
 
 LOCAL_C_INCLUDES +=\
     external/libpng\