lib/locale.t: Failures on FreeBSD-11.0

        O = OK  F = Failure(s)
        ---------------------- ----------------------------------------------------
        F  F                     (*1)
        F  F                    -Duseithreads (*1)
        |  |
        |  +------------------  stdio DEBUGGING
        +---------------------  stdio

        Test failures:
        ~~ ../lib/locale.t ............................................. FAILED No plan found in TAP output
          [stdio] 
          [stdio] -Duseithreads DEBUGGING
          [stdio]  DEBUGGING
          [stdio] -Duseithreads