Add a build to prove that the previous commit fixes #243

.gitlab-ci.yml

@@ -1,5 +1,5 @@
 # .gitlab-ci.yml -- to test some source code build scenarios
-# Copyright (C) 2016-2019  Olaf Meeuwissen
+# Copyright (C) 2016-2020  Olaf Meeuwissen
 #
 # License: GPL-3.0+
 
@@ -88,6 +88,13 @@ alpine-3.11-musl:
     CONFIGURE_OPTS: "$CONFIGURE_MINI $CONFIGURE_FULL"
   <<: *compile_definition
 
+ubuntu-16.04-lts:
+  image: $REGISTRY_HUB:ubuntu-xenial-dist
+  variables:
+    CONFIGURE_OPTS: "$CONFIGURE_MINI $CONFIGURE_FULL"
+    MAKE_FLAGS: "CFLAGS=-Werror CXXFLAGS=-Werror"
+  <<: *compile_definition
+
 # This snapshot stage job makes sure that the source tarball has all
 # it needs to rebuild itself, install everything built and cleans up
 # without leaving any droppings behind when uninstalling.  The build