CALL ERRMSG( STRING [,NCHRS] )  --  This routine outputs a message
 to the user's terminal (TI0:).  If NCHRS is not present, string
 is output to first zero byte.  For example,
 
 	CALL ERRMSG( 'Ooops! You made a boo-boo.' )
 
 NCHRS isn't needed since the FORTRAN compiler constructs
 delimited strings with at least one zero byte at the end.