Fix some unchecked Windows date provider retvals

src-input/duk_bi_date_windows.c

@@ -96,6 +96,7 @@ DUK_INTERNAL duk_int_t duk_bi_date_get_local_tzoffset_windows(duk_double_t d) {
 	ULARGE_INTEGER tmp2;
 	ULARGE_INTEGER tmp3;
 	FILETIME ft1;
+	BOOL ret;
 
 	/* XXX: handling of timestamps outside Windows supported range.
 	 * How does Windows deal with dates before 1600?  Does windows
@@ -115,7 +116,11 @@ DUK_INTERNAL duk_int_t duk_bi_date_get_local_tzoffset_windows(duk_double_t d) {
 
 	ft1.dwLowDateTime = tmp2.LowPart;
 	ft1.dwHighDateTime = tmp2.HighPart;
-	FileTimeToSystemTime((const FILETIME *) &ft1, &st2);
+	ret = FileTimeToSystemTime((const FILETIME *) &ft1, &st2);
+	if (!ret) {
+		DUK_D(DUK_DPRINT("FileTimeToSystemTime() failed, return tzoffset 0"));
+		return 0;
+	}
 	if (SystemTimeToTzSpecificLocalTime((LPTIME_ZONE_INFORMATION) NULL, &st2, &st3) == 0) {
 		DUK_D(DUK_DPRINT("SystemTimeToTzSpecificLocalTime() failed, return tzoffset 0"));
 		return 0;
@@ -135,6 +140,7 @@ DUK_INTERNAL duk_int_t duk_bi_date_get_local_tzoffset_windows_no_dst(duk_double_
 	FILETIME ft2;
 	ULARGE_INTEGER tmp1;
 	ULARGE_INTEGER tmp2;
+	BOOL ret;
 
 	/* Do a similar computation to duk_bi_date_get_local_tzoffset_windows
 	 * but without accounting for daylight savings time.  Use this on
@@ -150,9 +156,17 @@ DUK_INTERNAL duk_int_t duk_bi_date_get_local_tzoffset_windows_no_dst(duk_double_
 
 	ft1.dwLowDateTime = tmp1.LowPart;
 	ft1.dwHighDateTime = tmp1.HighPart;
-	FileTimeToLocalFileTime((const FILETIME *) &ft1, &ft2);
+	ret = FileTimeToLocalFileTime((const FILETIME *) &ft1, &ft2);
+	if (!ret) {
+		DUK_D(DUK_DPRINT("FileTimeToLocalFileTime() failed, return tzoffset 0"));
+		return 0;
+	}
 
-	FileTimeToSystemTime((const FILETIME *) &ft2, &st2);
+	ret = FileTimeToSystemTime((const FILETIME *) &ft2, &st2);
+	if (!ret) {
+		DUK_D(DUK_DPRINT("FileTimeToSystemTime() failed, return tzoffset 0"));
+		return 0;
+	}
 	duk__convert_systime_to_ularge((const SYSTEMTIME *) &st2, &tmp2);
 
 	return (duk_int_t) (((LONGLONG) tmp2.QuadPart - (LONGLONG) tmp1.QuadPart) / DUK_I64_CONSTANT(10000000));  /* seconds */