Fixed header reordering breaking hpvm-cava

hpvm/test/hpvm-cava/src/load_cam_model.c

 #include "load_cam_model.h"
-#include "pipe_stages.h"
 #include "utility.h"
 #include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
+// clang-format: pipe_stages.h must come after stdlib.h
+#include "pipe_stages.h"
 #include <string.h>
 
 // Get color space transform

hpvm/test/hpvm-cava/src/pipe_stages.h

@@ -2,6 +2,7 @@
 #define _PIPE_STAGES_H_
 
 #include "defs.h"
+#include <stddef.h>
 
 #define CHAN_SIZE 3