ffhist uses uninitialized histData fields

[wrp]

File: histo.c
Function: ffhist

The ffhist function declares a local histType structure without
initialization and fails to initialize the numIterCols, iterCols,
parsers, and startCols fields. When ffwritehisto is called, it
invokes fits_iterate_data with these uninitialized values, causing
undefined behavior (typically BAD_COL_NUM error 302 or segfault).

The ffhist3 function works correctly because it calls fits_make_histd
which properly initializes all histData fields.

Workaround: Use ffhist3 instead of ffhist.

Reproduction:

    fitsfile *f;
    int status = 0;
    char colname[4][FLEN_VALUE] = {"X", "", "", ""};
    double minin[4] = {0}, maxin[4] = {6}, binsizein[4] = {1};
    char minname[4][FLEN_VALUE] = {""};
    char maxname[4][FLEN_VALUE] = {""};
    char binname[4][FLEN_VALUE] = {""};

    /* Create and open a table with column X ... */
    fits_open_file(&f, "table.fits[1]", READWRITE, &status);
    ffhist(&f, "!hist.fits", TINT, 1, colname,
            minin, maxin, binsizein,
            minname, maxname, binname,
            1.0, "", 0, NULL, &status);
    /* status is 302 (BAD_COL_NUM) */