contrib: Enable -Werror by default

Change-Id: I1752cad1e34cb6e5f36edf3f538d803eff29d18c
diff --git a/contrib/jenkins-arm.sh b/contrib/jenkins-arm.sh
index d5fc31f..510b0e9 100755
--- a/contrib/jenkins-arm.sh
+++ b/contrib/jenkins-arm.sh
@@ -10,7 +10,7 @@
 	--host=arm-none-eabi \
 	--enable-embedded \
 	--disable-shared \
-	CFLAGS="-Os -ffunction-sections -fdata-sections -nostartfiles -nodefaultlibs"
+	CFLAGS="-Os -ffunction-sections -fdata-sections -nostartfiles -nodefaultlibs -Werror"
 
 $MAKE $PARALLEL_MAKE \
 	|| cat-testlogs.sh
@@ -27,7 +27,7 @@
 	--host=arm-none-eabi \
 	--enable-embedded \
 	--disable-shared \
-	CFLAGS="-Os -ffunction-sections -fdata-sections -nostartfiles -nodefaultlibs"
+	CFLAGS="-Os -ffunction-sections -fdata-sections -nostartfiles -nodefaultlibs -Werror"
 
 $MAKE $PARALLEL_MAKE \
 	|| cat-testlogs.sh