Revert "Revert "Fix warnings in servicemanager and KeyCharacterMap""

This reverts commit b480269b0f8e933fa6fc6bd4c9e1e504e1b51508.

Change-Id: If405c0786c5bdd02e3f2c3356d56a4200c6b9dfb
diff --git a/cmds/servicemanager/Android.mk b/cmds/servicemanager/Android.mk
index 7ee0dd1..73c0367 100644
--- a/cmds/servicemanager/Android.mk
+++ b/cmds/servicemanager/Android.mk
@@ -1,7 +1,7 @@
 LOCAL_PATH:= $(call my-dir)
 
 svc_c_flags =	\
-	-Wall -Wextra \
+	-Wall -Wextra -Werror \
 
 ifneq ($(TARGET_USES_64_BIT_BINDER),true)
 ifneq ($(TARGET_IS_64_BIT),true)