declare one tag

Tells LockLint that only one unnamed instance exists of each structure whose tag is specified. This knowledge makes it possible for LockLint to give an error if a lock in that structure is acquired multiple times without being released. Without this knowledge, LockLint does not complain about multiple acquisitions of anonymous locks (for example, foo::lock), since two different instances of the structure could be involved. (See "Lock Inversions".)