+ Only do this check on the very first call from
+ context_read(), when opp is NULL. That way, entries in
+ mhn.defaults can be overridden without triggering
+ warnings.
+
+ Note that that mhn.defaults, $MHN, $MHBUILD, $MHSHOW, and
+ $MHSTORE all put their entries into just one list, m_defs,
+ the same list that the profile uses. */
+
+ struct node *np;