Unconsistent iconv appendixes //TRANSLIT and //IGNORE

[Miguel Sacristan Izcue]

The appendixes of //TRANSLIT and //IGNORE can not work together on the same call.
It appears that it only works the first one to appear.

Example Code:
#########################################
#include <iconv.h>
#include <iostream>
#include <memory>
#include <cstring>
#include <string>
#include <utf8.h>

int main()
{
        const std::string in = "\xc5\xbd";
        iconv_t cd = iconv_open("ISO8859-1//TRANSLIT//IGNORE", "UTF-8");
        const char* inbuffer = in.c_str();
        char outbuffer[in.length()*2+1];
        memset(outbuffer, 0, in.length()*2+1);
        size_t srclen = in.length();
        size_t targetlen = in.length()*2+1;
        char* wrptr = outbuffer;
        iconv(cd,const_cast<char **>(&inbuffer), &srclen, &wrptr, &targetlen);
        iconv_close(cd);

        std::cout << outbuffer << std::endl;
}
########################################

With "//TRANSLIT" first:
 - "?"
WITH "//IGNORE" first:
 - ""

I am expecting to work together so that if there is a translit for that character it translates it and if there is non it just ignores it instead of writing a "?".

This is at least the behaviour i get when compiling in other platforms (FreeBSD)

An while we are it we could add a translit for this specific case so that "\xc5\xbd" => "Z" ?

Thanks in Advance

- lsb_release -rd:
UBUNTU 18.04.01 LTS
- Package version:
libglib2.0-dev:
  Installed: 2.56.2-0ubuntu0.18.04.2