+# ensure the ENV variable is well defined
+ifeq ($(origin ENV), prod)
+ # all good ("prod" is a valid env)
+else ifeq ($(origin ENV), dev)
+ # all good ("dev" is a valid env)
+else ifeq ($(origin ENV), test)
+ # all good ("test" is a valid env)
+else
+ # not good, force it to "prod"
+ override ENV = prod
+endif