[cvs-nhc98] patch applied (hat): In the basic Hat C routines:

[Malcolm Wallace]

Wed May  1 06:51:58 PDT 2002  malcolm
  * In the basic Hat C routines:
    * Use the ErrorMessage pointer in the .hat header to distinguish
      between _|_ and ^C.
    * Open the .hat.bridge file at the same time as the .hat file, and
      add error checking on the header, filesize, etc.
    * Fix a couple of bugs where routines forgot to check for a FileOffset
      in the range 0-4 (Root..Lambda)

    M ./src/hattools/artutils.c -12 +54