patch 8.2.4109: MS-Windows: high dpi support is outdated

Problem:    MS-Windows: high dpi support is outdated.
Solution:   Improve High DPI support by using PerMonitorV2. (closes #9525,
            closes #3102)
diff --git a/src/gui.h b/src/gui.h
index 46d2047..0bd29fc 100644
--- a/src/gui.h
+++ b/src/gui.h
@@ -424,7 +424,7 @@
 #endif
 
 #if defined(FEAT_TOOLBAR) \
-	&& (defined(FEAT_GUI_ATHENA) || defined(FEAT_GUI_MOTIF) || defined(FEAT_GUI_HAIKU))
+	&& (defined(FEAT_GUI_ATHENA) || defined(FEAT_GUI_MOTIF) || defined(FEAT_GUI_HAIKU) || defined(FEAT_GUI_MSWIN))
     int		toolbar_height;	    // height of the toolbar
 #endif