libiconv convert utf8 to gbk fialed when text contains `ellipsis(……)` only in iOS17

libiconv convert utf8 to gbk fialed when text contains ellipsis(……) only in iOS17, and in Xcode 15 I update the libiconv because it's old.

I have test libiconv.tbd and libicon.2.tbd the same result.

Condition:

1. only iOS 17, iOS 16- is OK;
2. Text contains ellipsis(……) such as ……测试字符串;
3. Convert to gbk or gb18030 is failed and return -1, but gb2312 return is OK。

int code_convert(const char *from_charset, const char *to_charset, char *inbuf, size_t inlen,
                 char *outbuf, size_t outlen) {
    iconv_t cd;
    char **pin = &inbuf;
    char **pout = &outbuf;

    cd = iconv_open(to_charset, from_charset);
    if (cd == 0)
        return -1;

    memset(outbuf, 0, outlen);

    if ((int)iconv(cd, pin, &inlen, pout, &outlen) == -1)
    {
        iconv_close(cd);
        std::cout<< "转换失败" << std::endl;
        return -1;
    }
    iconv_close(cd);
    

    return 0;
}

int u2g(char *inbuf, size_t inlen, char *outbuf, size_t outlen) {
    //gb18030 , gb2312
    return code_convert("utf-8", "gb2312", inbuf, inlen, outbuf, outlen);
}

std::string UTFtoGBK(const char* utf8)
{
    int length = strlen(utf8);

    char *temp = (char*)malloc(sizeof(char)*length);

    if(u2g((char*)utf8,length,temp,length) >= 0)
    {
        std::string str_result;
        str_result.append(temp);
        free(temp);

        return str_result;
    }else
    {
        free(temp);
        return "";
    }
}