Add dependencies on all the makefiles.

This should help prevent broken builds next time I'm messing with
assembler/compiler/linker flags...

Change-Id: I30f15a3ce3c3f3c60cad7bc59aaba9f42d792224
diff --git a/libthread_db/Android.mk b/libthread_db/Android.mk
index af506ed..5defe01 100644
--- a/libthread_db/Android.mk
+++ b/libthread_db/Android.mk
@@ -1,7 +1,7 @@
 LOCAL_PATH:= $(call my-dir)
 
 #
-# static 
+# static
 #
 
 include $(CLEAR_VARS)
@@ -10,6 +10,7 @@
 	libthread_db.c
 
 LOCAL_MODULE:= libthread_db
+LOCAL_ADDITIONAL_DEPENDENCIES := $(LOCAL_PATH)/Android.mk
 
 include $(BUILD_STATIC_LIBRARY)
 
@@ -20,7 +21,8 @@
 include $(CLEAR_VARS)
 
 LOCAL_WHOLE_STATIC_LIBRARIES := libthread_db
-LOCAL_MODULE:=libthread_db
+LOCAL_MODULE := libthread_db
+LOCAL_ADDITIONAL_DEPENDENCIES := $(LOCAL_PATH)/Android.mk
 LOCAL_SHARED_LIBRARIES := libdl libc
 LOCAL_ALLOW_UNDEFINED_SYMBOLS := false
 LOCAL_SYSTEM_SHARED_LIBRARIES :=