diff --git a/common/jack/systemdeps.h b/common/jack/systemdeps.h
index 6b1b8a7f..4806533b 100644
--- a/common/jack/systemdeps.h
+++ b/common/jack/systemdeps.h
@@ -1,5 +1,5 @@
 /*
-Copyright (C) 2004-2009 Grame
+Copyright (C) 2004-2012 Grame
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU Lesser General Public License as published by
@@ -20,66 +20,101 @@ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 #ifndef __jack_systemdeps_h__
 #define __jack_systemdeps_h__
 
-#if defined(WIN32) && !defined(__CYGWIN__) && !defined(GNU_WIN32)
+#ifndef POST_PACKED_STRUCTURE
+
+    #ifdef __GNUC__
+        /* POST_PACKED_STRUCTURE needs to be a macro which
+           expands into a compiler directive. The directive must
+           tell the compiler to arrange the preceding structure
+           declaration so that it is packed on byte-boundaries rather 
+           than use the natural alignment of the processor and/or
+           compiler.
+        */
+
+        #define PRE_PACKED_STRUCTURE
+        #define POST_PACKED_STRUCTURE __attribute__((__packed__))
+
+    #else
+    
+        #ifdef _MSC_VER
+            #define PRE_PACKED_STRUCTURE1 __pragma(pack(push,1))
+            #define PRE_PACKED_STRUCTURE    PRE_PACKED_STRUCTURE1
+            /* PRE_PACKED_STRUCTURE needs to be a macro which
+            expands into a compiler directive. The directive must
+            tell the compiler to arrange the following structure
+            declaration so that it is packed on byte-boundaries rather
+            than use the natural alignment of the processor and/or
+            compiler.
+            */
+            #define POST_PACKED_STRUCTURE ;__pragma(pack(pop))
+            /* and POST_PACKED_STRUCTURE needs to be a macro which
+            restores the packing to its previous setting */
+        #endif
 
-#include <windows.h>
-
-#ifdef _MSC_VER     /* Microsoft compiler */
-    #define __inline__ inline
-    #if (!defined(int8_t) && !defined(_STDINT_H))
-        #define __int8_t_defined
-        typedef char int8_t;
-        typedef unsigned char uint8_t;
-        typedef short int16_t;
-        typedef unsigned short uint16_t;
-        typedef long int32_t;
-        typedef unsigned long uint32_t;
-        typedef LONGLONG int64_t;
-        typedef ULONGLONG uint64_t;
     #endif
-#elif __MINGW32__   /* MINGW */
-    #include <stdint.h>
-    #include <sys/types.h>
-#else               /* other compilers ...*/
-    #include <inttypes.h>
-    #include <pthread.h>
-    #include <sys/types.h>
+
 #endif
 
-#if !defined(_PTHREAD_H) && !defined(PTHREAD_WIN32)
-    /**
-     *  to make jack API independent of different thread implementations,
-     *  we define jack_native_thread_t to HANDLE here.
-     */
-    typedef HANDLE jack_native_thread_t;
-#else
-    #ifdef PTHREAD_WIN32            // Added by JE - 10-10-2011
-        #include <ptw32/pthread.h>  // Makes sure we #include the ptw32 version !
+#if defined(WIN32) && !defined(__CYGWIN__) && !defined(GNU_WIN32)
+
+    #include <windows.h>
+
+    #ifdef _MSC_VER     /* Microsoft compiler */
+        #define __inline__ inline
+        #if (!defined(int8_t) && !defined(_STDINT_H))
+            #define __int8_t_defined
+            typedef char int8_t;
+            typedef unsigned char uint8_t;
+            typedef short int16_t;
+            typedef unsigned short uint16_t;
+            typedef long int32_t;
+            typedef unsigned long uint32_t;
+            typedef LONGLONG int64_t;
+            typedef ULONGLONG uint64_t;
+        #endif
+    #elif __MINGW32__   /* MINGW */
+        #include <stdint.h>
+        #include <sys/types.h>
+    #else               /* other compilers ...*/
+        #include <inttypes.h>
+        #include <pthread.h>
+        #include <sys/types.h>
+    #endif
+
+    #if !defined(_PTHREAD_H) && !defined(PTHREAD_WIN32)
+        /**
+         *  to make jack API independent of different thread implementations,
+         *  we define jack_native_thread_t to HANDLE here.
+         */
+        typedef HANDLE jack_native_thread_t;
+    #else
+        #ifdef PTHREAD_WIN32            // Added by JE - 10-10-2011
+            #include <ptw32/pthread.h>  // Makes sure we #include the ptw32 version !
+        #endif
+        /**
+         *  to make jack API independent of different thread implementations,
+         *  we define jack_native_thread_t to pthread_t here.
+         */
+        typedef pthread_t jack_native_thread_t;
     #endif
-    /**
-     *  to make jack API independent of different thread implementations,
-     *  we define jack_native_thread_t to pthread_t here.
-     */
-    typedef pthread_t jack_native_thread_t;
-#endif
 
 #endif // WIN32 && !__CYGWIN__ && !GNU_WIN32 */
 
 #if defined(__APPLE__) || defined(__linux__) || defined(__sun__) || defined(sun) || defined(__unix__) || defined(__CYGWIN__) || defined(GNU_WIN32)
 
-#if defined(__CYGWIN__) || defined(GNU_WIN32)
-    #include <stdint.h>
-#endif
-    #include <inttypes.h>
-    #include <pthread.h>
-    #include <sys/types.h>
+    #if defined(__CYGWIN__) || defined(GNU_WIN32)
+        #include <stdint.h>
+    #endif
+        #include <inttypes.h>
+        #include <pthread.h>
+        #include <sys/types.h>
 
-    /**
-     *  to make jack API independent of different thread implementations,
-     *  we define jack_native_thread_t to pthread_t here.
-     */
-    typedef pthread_t jack_native_thread_t;
+        /**
+         *  to make jack API independent of different thread implementations,
+         *  we define jack_native_thread_t to pthread_t here.
+         */
+        typedef pthread_t jack_native_thread_t;
 
-#endif /* __APPLE__ || __linux__ || __sun__ || sun */
+    #endif /* __APPLE__ || __linux__ || __sun__ || sun */
 
 #endif
diff --git a/common/jack/types.h b/common/jack/types.h
index a7d06983..cfad3e54 100644
--- a/common/jack/types.h
+++ b/common/jack/types.h
@@ -548,6 +548,7 @@ typedef enum {
 #define JACK_POSITION_MASK (JackPositionBBT|JackPositionTimecode)
 #define EXTENDED_TIME_INFO
 
+PRE_PACKED_STRUCTURE
 typedef struct {
 
     /* these four cannot be set from clients: the server sets them */
@@ -614,7 +615,7 @@ typedef struct {
     /* When (unique_1 == unique_2) the contents are consistent. */
     jack_unique_t       unique_2;       /**< unique ID */
 
-} jack_position_t;
+} POST_PACKED_STRUCTURE jack_position_t;
 
 /**
     * Prototype for the @a sync_callback defined by slow-sync clients.