static int yy_init_globals (yyscan_t yyscanner)
{
    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
    /* Initialization is the same as for the non-reentrant scanner.
     * This function is called from re_yylex_destroy(), so don't allocate here.
     */

    yyg->yy_buffer_stack = 0;
    yyg->yy_buffer_stack_top = 0;
    yyg->yy_buffer_stack_max = 0;
    yyg->yy_c_buf_p = (char *) 0;
    yyg->yy_init = 0;
    yyg->yy_start = 0;

    yyg->yy_start_stack_ptr = 0;
    yyg->yy_start_stack_depth = 0;
    yyg->yy_start_stack =  NULL;

/* Defined in main.c */
#ifdef YY_STDINIT
    yyin = stdin;
    yyout = stdout;
#else
    yyin = (FILE *) 0;
    yyout = (FILE *) 0;
#endif

    /* For future reference: Set errno on error, since we are called by
     * re_yylex_init()
     */
    return 0;
}

The product dereferences a pointer that it expects to be valid but is NULL.