Use new -ninja flag to aidl-cpp
This make aidl-cpp write out a dep file that ninja parses correctly.
Test: Manually inspect ninja depfile
Change-Id: I4890a91eb29a6388e17b1ffac23a3dc0ffe6c212
diff --git a/core/definitions.mk b/core/definitions.mk
index 2e7c9b3..7a42ad8 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -1063,7 +1063,7 @@
@mkdir -p $(dir $@)
@mkdir -p $(PRIVATE_HEADER_OUTPUT_DIR)
@echo "Generating C++ from AIDL: $(PRIVATE_MODULE) <= $<"
-$(hide) $(AIDL_CPP) -d$(basename $@).aidl.P $(PRIVATE_AIDL_FLAGS) \
+$(hide) $(AIDL_CPP) -d$(basename $@).aidl.d -ninja $(PRIVATE_AIDL_FLAGS) \
$< $(PRIVATE_HEADER_OUTPUT_DIR) $@
endef