[common] Update framebuffer metadata + references

common/include/common/framebuffer.h

@@ -24,16 +24,21 @@
 #include <stdlib.h>
 #include <stdbool.h>
 #include <stdint.h>
+#include <stdatomic.h>
 
-typedef struct stFrameBuffer FrameBuffer;
+#define FB_CHUNK_SIZE           1048576 // 1MB
+#define FB_SPIN_LIMIT           10000   // 10ms
+#define FB_WP_TYPE              atomic_uint_least32_t
+#define FB_WP_SIZE              sizeof(FB_WP_TYPE)
+
+typedef struct stFrameBuffer
+{
+  FB_WP_TYPE wp;
+  uint8_t    data[0];
+} FrameBuffer;
 
 typedef bool (*FrameBufferReadFn)(void * opaque, const void * src, size_t size);
 
-/**
- * The size of the FrameBuffer struct
- */
-extern const size_t FrameBufferStructSize;
-
 /**
  * Wait for the framebuffer to fill to the specified size
  */