Turn unusual tags into errors

# makefiles. Anything else is either a typo or a source of unexpected

# behaviors.

ifneq ($(filter-out debug eng tests optional samples,$(my_module_tags)),)

$(call pretty-warning,unusual tags $(my_module_tags))

$(call pretty-error,unusual tags: $(filter-out debug eng tests optional samples,$(my_module_tags)))

endif

# Add implicit tags.