I thought SAL_WARN_IF etc worked in such a way that any variables used
in the condition would be "used" from the compiler's point of view,
even in an optimising build case where SAL_DETAIL_ENABLE_LOG_WARN is
false and SAL_WARN_IF should optimise away?

Change-Id: I728e1eeb8559e1299abf403afceb0e2748d08857