Enable 'mysys' build if target 'Enterprise'
item_subselect.h:
  Fixed bug #27870. The bug that causes crashes manifests itself at some
  conditions when executing an equijoin query with WHERE condition
  containing a subquery predicate of the form join_attr NOT IN (SELECT ...).


VC++Files/mysql.sln:
  Enable 'mysys' build if target 'Enterprise'
sql/item_subselect.h:
  Fixed bug #27870. The bug that causes crashes manifests itself at some
  conditions when executing an equijoin query with WHERE condition
  containing a subquery predicate of the form join_attr NOT IN (SELECT ...).