Security fixes: expect final changes for release 1.75.3.
* Fixed a debian security issue with fscanf() reading a string with
  possible buffer overflow.
* There were also a few similar situations with sscanf().
ptaGetPt(PTA        *pta,
         l_int32     index,
         l_float32  *px,
         l_float32  *py)
{
    PROCNAME("ptaGetPt");

    if (px) *px = 0;
    if (py) *py = 0;
    if (!pta)
        return ERROR_INT("pta not defined", procName, 1);
    if (index < 0 || index >= pta->n)
        return ERROR_INT("invalid index", procName, 1);

    if (px) *px = pta->x[index];
    if (py) *py = pta->y[index];
    return 0;
}

ptaGetPt(PTA        *pta,
         l_int32     index,
         l_float32  *px,
         l_float32  *py)
{
    PROCNAME("ptaGetPt");

    if (px) *px = 0;
    if (py) *py = 0;
    if (!pta)
        return ERROR_INT("pta not defined", procName, 1);
    if (index < 0 || index >= pta->n)
        return ERROR_INT("invalid index", procName, 1);

    if (px) *px = pta->x[index];
    if (py) *py = pta->y[index];
    return 0;
}
