Use -Werror in external/arm-neon-tests

* Suppress existing warnings.

Bug: 66996870
Test: build with WITH_TIDY=1
Change-Id: I99874979419ca367a46ab8ca659c55934bd42b2e
diff --git a/Android.mk b/Android.mk
index a330390..2dfc488 100644
--- a/Android.mk
+++ b/Android.mk
@@ -50,6 +50,15 @@
 ARM_NEON_TESTS_CFLAGS = -DREFFILE=\"$(ARM_NEON_TESTS_REFGCCARM)\" \
                         -DGCCTESTS_FILE=\"$(ARM_NEON_TESTS_EXPECTED_INPUT)\"
 
+ARM_NEON_TESTS_CFLAGS += \
+     -Wall \
+     -Werror \
+     -Wno-format \
+     -Wno-ignored-qualifiers \
+     -Wno-uninitialized \
+     -Wno-unused-function \
+     -Wno-unused-variable \
+
 include $(CLEAR_VARS)
 LOCAL_MODULE := arm_neon_tests_arm
 LOCAL_ARM_MODE := arm