fixed compiler warnings
diff --git a/progs/demos/shadow.c b/progs/demos/shadow.c
index a1b3fde..0f66b53 100644
--- a/progs/demos/shadow.c
+++ b/progs/demos/shadow.c
@@ -48,6 +48,8 @@
 /* Rendering shadows using projective shadows. */
 
 #include <GL/glut.h>
+#include "shadow.h"
+
 
 enum {
   X, Y, Z, W