diff --git a/mps/code/mpmst.h b/mps/code/mpmst.h
index 1905e2bb560..739c95a449d 100644
--- a/mps/code/mpmst.h
+++ b/mps/code/mpmst.h
@@ -223,7 +223,6 @@ typedef struct MessageStruct {
   MessageType type;             /* Message Type */
   MessageClass class;           /* Message Class Structure */
   RingStruct queueRing;         /* Message queue ring */
-  mps_clock_t postedClock;      /* mps_clock() at post time */
 } MessageStruct;
 
 
diff --git a/mps/code/mpslib.h b/mps/code/mpslib.h
index f74bd986fa6..094975b3cf7 100644
--- a/mps/code/mpslib.h
+++ b/mps/code/mpslib.h
@@ -14,7 +14,7 @@
 #define mpslib_h
 
 #include <stddef.h>
-#include "mps.h"  /* mps_clock_t */
+
 
 extern int mps_lib_get_EOF(void);
 #define mps_lib_EOF     (mps_lib_get_EOF())
@@ -36,6 +36,7 @@ extern void *(mps_lib_memcpy)(void *, const void *, size_t);
 extern int (mps_lib_memcmp)(const void *, const void *, size_t);
 
 
+typedef unsigned long mps_clock_t;
 extern mps_clock_t mps_clock(void);
 extern mps_clock_t mps_clocks_per_sec(void);