// computing build id
XRCORE_API    LPCSTR    build_date;
XRCORE_API    u32        build_id;

...

static LPSTR month_id[12] = {
    "Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"
};

static int days_in_month[12] = {
    31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};

static int start_day    = 31;    // 31
static int start_month    = 1;    // January
static int start_year    = 1999;    // 1999

...

void compute_build_id    ()
{
    build_date            = __DATE__;

    int                    days;
    int                    months = 0;
    int                    years;
    string16            month;
    string256            buffer;
    xr_strcpy                (buffer,__DATE__);
    sscanf                (buffer,"%s %d %d",month,&days,&years);

    for (int i=0; i<12; i++) {
        if (_stricmp(month_id[i],month))
            continue;

        months            = i;
        break;
    }

    build_id            = (years - start_year)*365 + days - start_day;

    for (int i=0; i<months; ++i)
        build_id        += days_in_month[i];

    for (int i=0; i<start_month-1; ++i)
        build_id        -= days_in_month[i];
}

//...
if (0) {
    terminate();
}
//...