Add wxBitmap ctor from wxCursor to wxGTK and wxMSW.

Allow converting wxCursor to wxBitmap in order to draw it, for example.

Closes #15699.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77537 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/bitmap.h

@@ -346,6 +346,21 @@ public:
     */
     wxBitmap(const wxImage& img, int depth = wxBITMAP_SCREEN_DEPTH);
 
+    /**
+        Creates bitmap corresponding to the given cursor.
+
+        This can be useful to display a cursor as it cannot be drawn directly
+        on a window.
+
+        This constructor only exists in wxMSW and wxGTK (where it is
+        implemented for GTK+ 2.8 or later) only.
+
+        @param cursor A valid wxCursor.
+
+        @since 3.1.0
+    */
+    explicit wxBitmap(const wxCursor& cursor);
+
     /**
         Destructor.
         See @ref overview_refcount_destruct for more info.