gdi32: Fix CreateCompatibleDC to reject invalid DCs.

dlls/gdi32/dc.c

@@ -785,6 +785,7 @@ HDC WINAPI CreateCompatibleDC( HDC hdc )
         release_dc_ptr( origDC );
         if (funcs) funcs = DRIVER_get_driver( funcs );
     }
+    else if (hdc) return 0;
 
     if (!funcs && !(funcs = DRIVER_load_driver( displayW ))) return 0;
 

dlls/gdi32/tests/dc.c

@@ -248,15 +248,11 @@ static void test_CreateCompatibleDC(void)
     bRet = DeleteDC(hDC);
     ok(bRet == TRUE, "DeleteDC returned %u\n", bRet);
 
-todo_wine
-{
     /* Try to create a DC compatible to the deleted DC. This has to fail */
     hNewDC = CreateCompatibleDC(hDC);
     ok(hNewDC == NULL, "CreateCompatibleDC returned %p\n", hNewDC);
 }
 
-}
-
 START_TEST(dc)
 {
     test_savedc();