turn off warning that proto generated code causes.

Test: make
Change-Id: Ife3006dc16691dd95a2cc3d36c9b8832970601c9
diff --git a/tools/incident_report/Android.mk b/tools/incident_report/Android.mk
index ed89bd6..9e56e3d 100644
--- a/tools/incident_report/Android.mk
+++ b/tools/incident_report/Android.mk
@@ -34,6 +34,8 @@
     libplatformprotos \
     libprotobuf-cpp-full
 
+LOCAL_C_FLAGS := \
+    -Wno-unused-parameter
 include $(BUILD_HOST_EXECUTABLE)