oleaut32: Fixed VARIANT_FormatDate behavior on dates before year 1600.

dlls/oleaut32/varformat.c

@@ -1908,7 +1908,7 @@ static HRESULT VARIANT_FormatDate(LPVARIANT pVarIn, LPOLESTR lpszFormat,
       WCHAR fmt_buff[80];
 
       if (!GetLocaleInfoW(lcid, dwFmt, fmt_buff, sizeof(fmt_buff)/sizeof(WCHAR)) ||
-          !GetDateFormatW(lcid, 0, &udate.st, fmt_buff, pBuff,
+          !get_date_format(lcid, 0, &udate.st, fmt_buff, pBuff,
                           sizeof(buff)/sizeof(WCHAR)-(pBuff-buff)))
       {
         hRes = E_INVALIDARG;

dlls/oleaut32/variant.h

@@ -127,3 +127,5 @@ typedef struct tagVARIANT_NUMBER_CHARS
 
 BOOL VARIANT_GetLocalisedText(LANGID, DWORD, WCHAR *) DECLSPEC_HIDDEN;
 HRESULT VARIANT_ClearInd(VARIANTARG *) DECLSPEC_HIDDEN;
+BOOL get_date_format(LCID, DWORD, const SYSTEMTIME *,
+        const WCHAR *, WCHAR *, int) DECLSPEC_HIDDEN;

dlls/oleaut32/vartype.c

@@ -6596,7 +6596,7 @@ static inline int output_int_len(int o, int min_len, WCHAR *date, int date_len)
 }
 
 /* format date string, similar to GetDateFormatW function but works on bigger range of dates */
-static BOOL get_date_format(LCID lcid, DWORD flags, const SYSTEMTIME *st,
+BOOL get_date_format(LCID lcid, DWORD flags, const SYSTEMTIME *st,
         const WCHAR *fmt, WCHAR *date, int date_len)
 {
     static const LCTYPE dayname[] = {