avutil/parseutils: dont assume standard time when parsing a timestamp

Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: Marton Balint <cus@passwd.hu>

libavutil/parseutils.c

@@ -687,6 +687,7 @@ int av_parse_time(int64_t *timeval, const char *timestr, int duration)
             dt2.tm_sec  = dt.tm_sec;
             dt = dt2;
         }
+        dt.tm_isdst = is_utc ? 0 : -1;
         t = is_utc ? av_timegm(&dt) : mktime(&dt);
         t += tzoffset;
     }