Showing plist time issue, C version

PlistIssueDemo.c

#include <plist/plist.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <time.h>

#define MAC_EPOCH 978307200

static void parse_date(const char *strval, struct tm *btime)
{
    if (!btime) return;
    memset(btime, 0, sizeof(struct tm));
    if (!strval) return;
#ifdef strptime
    strptime((char*)strval, "%Y-%m-%dT%H:%M:%SZ", btime);
#else
    sscanf(strval, "%d-%d-%dT%d:%d:%dZ", &btime->tm_year, &btime->tm_mon, &btime->tm_mday, &btime->tm_hour, &btime->tm_min, &btime->tm_sec);
    btime->tm_year-=1900;
    btime->tm_mon--;
#endif
    btime->tm_isdst=0;
}

int main()
{
    char* xml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
        "<!DOCTYPE plist PUBLIC \"-//Apple//DTD PLIST 1.0//EN\" \"http://www.apple.com/DTDs/PropertyList-1.0.dtd\">\n"
        "<plist version=\"1.0\">\n"
        "<dict>\n"
        "<key>Last Backup Date</key>\n"
        "<date>2016-04-06T10:16:17Z</date>\n"
        "</dict>\n"
        "</plist>\n";

    printf("The xml is:\n%s\n==================\n", xml);

    plist_t dict = NULL;
    plist_from_xml(xml, strlen(xml), &dict);

    plist_t datetimeNode = plist_dict_get_item(dict, "Last Backup Date");

    int32_t sec, usec;
    plist_get_date_val(datetimeNode, &sec, &usec);

    printf("The date in secs = %d\n", sec);

    plist_free(dict);

    char* time = "2016-04-06T10:16:17Z";

    struct tm btime;
    struct tm* tm_utc;

    time_t timev = 0;

    parse_date((const char*)time, &btime);
    timev = mktime(&btime);
    tm_utc = gmtime(&timev);
    timev -= (mktime(tm_utc) - timev);

    printf("Another time: %ld\n", (long)(timev - MAC_EPOCH));

    return 0;
}