progs/trivial: Use glew where needed.

Builds on windows now.
diff --git a/progs/trivial/long-fixed-func.c b/progs/trivial/long-fixed-func.c
index 88f4fe0..41ad25c 100644
--- a/progs/trivial/long-fixed-func.c
+++ b/progs/trivial/long-fixed-func.c
@@ -5,7 +5,7 @@
 
 
 
-#define GL_GLEXT_PROTOTYPES
+#include <GL/glew.h>
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
@@ -142,6 +142,7 @@
     if (glutCreateWindow("tri-long-fixedfunc") == GL_FALSE) {
        exit(1);
     }
+    glewInit();
     glutReshapeFunc(Reshape);
     glutKeyboardFunc(Key);
     glutDisplayFunc(Draw);