fix gmt-offset on windows

extra/calendar/windows/windows.factor

@@ -1,22 +1,21 @@
 USING: calendar.backend namespaces alien.c-types
-windows windows.kernel32 kernel math ;
+windows windows.kernel32 kernel math combinators.cleave
+combinators ;
 IN: calendar.windows
 
 TUPLE: windows-calendar ;
 
 T{ windows-calendar } calendar-backend set-global
 
-: TIME_ZONE_ID_INVALID HEX: ffffffff ; inline
-
 M: windows-calendar gmt-offset ( -- hours minutes seconds )
-    0 0 0 ;
-    ! "TIME_ZONE_INFORMATION" <c-object>
-    ! dup GetTimeZoneInformation {
-    !     { [ dup TIME_ZONE_ID_INVALID = ] [ win32-error ] }
-    !     { [ dup { TIME_ZONE_ID_UNKNOWN TIME_ZONE_ID_STANDARD } member? ]
-    !         [ TIME_ZONE_INFORMATION-Bias 60 / neg ] }
-    !     { [ dup TIME_ZONE_ID_DAYLIGHT = ] [
-    !         [ TIME_ZONE_INFORMATION-Bias 60 / neg ]
-    !         [ TIME_ZONE_INFORMATION-DaylightBias ] bi
-    !     ] }
-    ! } cond ;
+    "TIME_ZONE_INFORMATION" <c-object>
+    dup GetTimeZoneInformation {
+        { [ dup TIME_ZONE_ID_INVALID = ] [ win32-error-string throw ] }
+        { [ dup [ TIME_ZONE_ID_UNKNOWN = ] [ TIME_ZONE_ID_STANDARD = ] bi or ] [
+            drop TIME_ZONE_INFORMATION-Bias ] }
+        { [ dup TIME_ZONE_ID_DAYLIGHT = ] [
+            drop
+            [ TIME_ZONE_INFORMATION-Bias ]
+            [ TIME_ZONE_INFORMATION-DaylightBias ] bi +
+        ] }
+    } cond neg 60 /mod 0 ;