Add wxCursor::GetHotSpot() and implement it for wxMSW and wxGTK.

Allow retrieving the coordinates of the cursor hot spot, at least for the
ports for which we know how to do it.

Closes #16539.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78134 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/cursor.h

@@ -214,6 +214,19 @@ public:
     */
     virtual bool IsOk() const;
 
+    /**
+        Returns the coordinates of the cursor hot spot.
+
+        The hot spot is the point at which the mouse is actually considered to
+        be when this cursor is used.
+
+        This method is currently only implemented in wxMSW and wxGTK2+ and
+        simply returns ::wxDefaultPosition in the other ports.
+
+        @since 3.1.0
+     */
+    wxPoint GetHotSpot() const;
+
     /**
         Assignment operator, using @ref overview_refcount "reference counting".
     */