free_pattern_expr  755 grep.c         		free_pattern_expr(x->u.unary);
free_pattern_expr  759 grep.c         		free_pattern_expr(x->u.binary.left);
free_pattern_expr  760 grep.c         		free_pattern_expr(x->u.binary.right);
free_pattern_expr  792 grep.c         	free_pattern_expr(opt->pattern_expression);