Avoid shifts of negative values inflateMark().

The C standard says that bit shifts of negative integers is
undefined.  This casts to unsigned values to assure a known
result.
int ZEXPORT inflateReset2(strm, windowBits)
z_streamp strm;
int windowBits;
{
    int wrap;
    struct inflate_state FAR *state;

    /* get the state */
    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;

    /* extract wrap request from windowBits parameter */
    if (windowBits < 0) {
        wrap = 0;
        windowBits = -windowBits;
    }
    else {
        wrap = (windowBits >> 4) + 1;
#ifdef GUNZIP
        if (windowBits < 48)
            windowBits &= 15;
#endif
    }

    /* set number of window bits, free window if different */
    if (windowBits && (windowBits < 8 || windowBits > 15))
        return Z_STREAM_ERROR;
    if (state->window != Z_NULL && state->wbits != (unsigned)windowBits) {
        ZFREE(strm, state->window);
        state->window = Z_NULL;
    }

    /* update state and reset the rest of it */
    state->wrap = wrap;
    state->wbits = (unsigned)windowBits;
    return inflateReset(strm);
}

int ZEXPORT inflateReset2(strm, windowBits)
z_streamp strm;
int windowBits;
{
    int wrap;
    struct inflate_state FAR *state;

    /* get the state */
    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
    state = (struct inflate_state FAR *)strm->state;

    /* extract wrap request from windowBits parameter */
    if (windowBits < 0) {
        wrap = 0;
        windowBits = -windowBits;
    }
    else {
        wrap = (windowBits >> 4) + 1;
#ifdef GUNZIP
        if (windowBits < 48)
            windowBits &= 15;
#endif
    }

    /* set number of window bits, free window if different */
    if (windowBits && (windowBits < 8 || windowBits > 15))
        return Z_STREAM_ERROR;
    if (state->window != Z_NULL && state->wbits != (unsigned)windowBits) {
        ZFREE(strm, state->window);
        state->window = Z_NULL;
    }

    /* update state and reset the rest of it */
    state->wrap = wrap;
    state->wbits = (unsigned)windowBits;
    return inflateReset(strm);
}
