pkg sync, method (*Cond) Broadcast()
pkg sync, method (*Cond) Signal()
pkg sync, method (*Cond) Wait()
pkg sync, method (*Mutex) Lock()
pkg sync, method (*Mutex) Unlock()
pkg sync, method (*Once) Do(func())
pkg sync, method (*RWMutex) Lock()
pkg sync, method (*RWMutex) RLock()
pkg sync, method (*RWMutex) RLocker() Locker
pkg sync, method (*RWMutex) RUnlock()
pkg sync, method (*RWMutex) Unlock()

   ensure that, in the event an Application does not supply the
   function or data, the facility still operates, and performs
   whatever part of its purpose remains meaningful, or

   b) under the GNU GPL, with none of the additional permissions of
   this License applicable to that copy.

  3. Object Code Incorporating Material from Library Header Files.