programs: Use WIN32_LEAN_AND_MEAN.
diff --git a/programs/winhelp/callback.c b/programs/winhelp/callback.c
index 3627547..aaa4eae 100644
--- a/programs/winhelp/callback.c
+++ b/programs/winhelp/callback.c
@@ -18,6 +18,8 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
+#define WIN32_LEAN_AND_MEAN
+
 #include <stdio.h>
 
 #include "windows.h"