diff --git a/examples/gears.pp b/examples/gears.pp
index 7fe518b..e4c97a1 100644
--- a/examples/gears.pp
+++ b/examples/gears.pp
@@ -12,13 +12,14 @@
 {$mode objfpc}
 
 uses
+  {$ifdef UNIX} CThreads, {$endif}
   StrUtils,
   GL,
   GLPT;
 
 (**
 
-  Draw a gear wheel.  You'll probably wglpt to call this function when
+  Draw a gear wheel.  You'll probably want to call this function when
   building a display list since we do a lot of trig here.
 
   Input:  inner_radius - radius of hole at center
@@ -193,7 +194,7 @@
       GLPT_SetWindowShouldClose(win, True);
   end;
 
-  procedure error_callback(const error: integer; const description: string);
+  procedure error_callback(error: integer; description: string);
   begin
     writeln(stderr, description);
   end;