Add initial prototype.

3-mid/opengl/source/platform/osmesa/opengl-display.adb

@@ -0,0 +1,25 @@
+with
+     interfaces.C.Strings;
+
+
+package body openGL.Display
+is
+
+
+   function Default return Item
+   is
+      Self    : Display.item;
+   begin
+      return Self;
+   end Default;
+
+
+
+   function screen_Id (Self : in Item) return interfaces.c.int
+   is
+   begin
+      return Self.screen_Id;
+   end screen_Id;
+
+
+end openGL.Display;