Add feedback packet. Proper header.

xlap.c

 #define XLAP
 #include "xlap.h"
 
-#include <stdatomic.h>
 
 void XlapTimestampTableDumpHeader(FILE *out)
 {

xlap.h

@@ -5,6 +5,13 @@
 #include <stdint.h>
 #include <time.h>
 
+#ifndef __cplusplus
+# include <stdatomic.h>
+#else
+# include <atomic>
+# define _Atomic(X) std::atomic< X >
+#endif
+
 /*
  * Each timestamp contains both a cycle value and a time value, but some values
  * might remain zero
@@ -64,6 +71,7 @@ typedef enum XlapTimestampPacketKind {
     ts_data_packet = 0,
     ts_any_packet = 0,
     ts_redundancy_packet = 1,
+    ts_feedback_packet = 2
 } XlapTimestampPacketKind;
 
 /*