%N bugv_c %F $MIR/src/subs/bug.c
%D Issue a dynamic error message, given by the caller.
%P pjt
%: error-handling
%B
C call sequence:
        bugv_c(severity,message,....)

  Output the error message given by the caller, and abort if needed.
  Note this routine has no counterpart in FORTRAN.

  Input:
    severity    Error severity character. 
                Can be one of 'i', 'w', 'e' or 'f'
                for "informational", "warning", "error", or "fatal"
    message     The error message string, can contain %-printf style 
                directives, as used by the following arguments.
     ...         Optional argument, in the printf() style               
