Support overrides in seapp_contexts

Provides support for overriding seapp_contexts declerations
in per device seapp_contexts files.

Change-Id: I23a0ffa1d24f1ce57825b168f29a2e885d3e1c51
diff --git a/Android.mk b/Android.mk
index 5eb3925..5481541 100644
--- a/Android.mk
+++ b/Android.mk
@@ -1,6 +1,9 @@
 ifeq ($(HAVE_SELINUX),true)
 
 LOCAL_PATH:= $(call my-dir)
+
+include $(call all-makefiles-under,$(LOCAL_PATH))
+
 include $(CLEAR_VARS)
 
 # SELinux policy version.
@@ -71,13 +74,16 @@
 
 include $(BUILD_SYSTEM)/base_rules.mk
 
-seapp_contexts := $(intermediates)/seapp_contexts
-$(seapp_contexts): $(LOCAL_PATH)/seapp_contexts $(LOCAL_POLICY_SC)
+seapp_contexts.conf := $(intermediates)/seapp_contexts.conf
+$(seapp_contexts.conf): $(LOCAL_PATH)/seapp_contexts $(LOCAL_POLICY_SC)
 	@mkdir -p $(dir $@)
 	$(hide) m4 -s $^ > $@
 
-seapp_contexts :=
+$(LOCAL_BUILT_MODULE) : $(seapp_contexts.conf) $(TARGET_ROOT_OUT)/sepolicy.$(POLICYVERS) $(HOST_OUT_EXECUTABLES)/checkseapp
+	@mkdir -p $(dir $@)
+	$(hide) $(HOST_OUT_EXECUTABLES)/checkseapp -p $(TARGET_ROOT_OUT)/sepolicy.24 -o $@ $<
 
+seapp_contexts.conf :=
 ##################################
 include $(CLEAR_VARS)