[cvs-nhc98] patch applied (hat): Enabled interruption of computation in tracing with new file format.

[Malcolm Wallace]

Tue Apr 16 09:00:23 PDT 2002  olaf
  * Enabled interruption of computation in tracing with new file format.
  
  The header marks interrution as decribed in Memo 31.
  Interruption can only happen when a reduction or a Forward node is entered. So a trusted or foreign computation cannot be interrupted.

    M ./src/hatlib/hat-c.c -10 +22