Use -Werror in external/libcap-ng

* Suppress enum-conversion and unused-parameter warnings.

Bug: 66996870
Test: build with WITH_TIDY=1
Change-Id: I050f18a8019110a5397ea9d8eb5b1dce32b77386
diff --git a/Android.mk b/Android.mk
index c0b7f3d..0c298b6 100644
--- a/Android.mk
+++ b/Android.mk
@@ -8,6 +8,10 @@
 
 LOCAL_C_INCLUDES += $(LOCAL_PATH)/libcap-ng-0.7/src
 LOCAL_MODULE := libcap-ng
+LOCAL_CFLAGS := \
+    -Wall -Werror \
+    -Wno-enum-conversion \
+    -Wno-unused-parameter
 include $(BUILD_SHARED_LIBRARY)
 
 ######################
@@ -17,7 +21,5 @@
 LOCAL_C_INCLUDES += $(LOCAL_PATH)/libcap-ng-0.7/src
 LOCAL_SHARED_LIBRARIES += libcap-ng
 LOCAL_MODULE := pscap
+LOCAL_CFLAGS := -Wall -Werror
 include $(BUILD_EXECUTABLE)
-
-
-