Implemented GetDaylightFlag.

dlls/kernel/kernel32.spec

@@ -381,7 +381,7 @@
 @ stdcall GetCurrentThreadId()
 @ stdcall GetDateFormatA(long long ptr str ptr long)
 @ stdcall GetDateFormatW(long long ptr wstr ptr long)
-@ stub GetDaylightFlag
+@ stdcall GetDaylightFlag()
 @ stdcall GetDefaultCommConfigA(str ptr long)
 @ stdcall GetDefaultCommConfigW(wstr ptr long)
 @ stub GetDefaultSortkeySize

dlls/kernel/time.c

@@ -155,6 +155,7 @@ BOOL WINAPI SetSystemTimeAdjustment(
  * RETURNS
  *  Success: TIME_ZONE_ID_STANDARD. tzinfo contains the time zone info.
  *  Failure: TIME_ZONE_ID_INVALID.
+ *  FIXME: return TIME_ZONE_ID_DAYLIGHT when daylight saving is on.
  */
 DWORD WINAPI GetTimeZoneInformation(
     LPTIME_ZONE_INFORMATION tzinfo) /* [out] Destination for time zone information */
@@ -871,3 +872,18 @@ VOID WINAPI GetSystemTime(LPSYSTEMTIME systime) /* [O] Destination for current t
     ft.dwHighDateTime = t.u.HighPart;
     FileTimeToSystemTime(&ft, systime);
 }
+
+/*********************************************************************
+ *      GetDaylightFlag                                   (KERNEL32.@)
+ *
+ *      returns TRUE if daylight saving time is in operation
+ *
+ *      Note: this function is called from the Win98's control applet
+ *      timedate.cpl
+ */
+BOOL WINAPI GetDaylightFlag(void)
+{
+    time_t t = time(NULL);
+    struct tm *ptm = localtime( &t);
+    return ptm->tm_isdst > 0;
+}