Enable strict warning checks and fix

Change-Id: Id401a937911eb418e93314812f2f7c2b5ecff8d6
diff --git a/services/soundtrigger/Android.mk b/services/soundtrigger/Android.mk
index e8e18b8..c55ac7f 100644
--- a/services/soundtrigger/Android.mk
+++ b/services/soundtrigger/Android.mk
@@ -40,6 +40,8 @@
 
 LOCAL_MULTILIB := $(AUDIOSERVER_MULTILIB)
 
+LOCAL_CFLAGS := -Wall -Werror
+
 LOCAL_MODULE:= libsoundtriggerservice
 
 include $(BUILD_SHARED_LIBRARY)