diff --git a/harbour/ChangeLog b/harbour/ChangeLog
index ca6d15f350..4bb501848a 100644
--- a/harbour/ChangeLog
+++ b/harbour/ChangeLog
@@ -17,6 +17,21 @@
    past entries belonging to author(s): Viktor Szakats.
 */
 
+2010-05-24 11:38 UTC+0200 Przemyslaw Czerpak (druzus/at/priv.onet.pl)
+  * harbour/include/hbapi.h
+  * harbour/include/hbvmint.h
+  * harbour/include/hbvmopt.h
+  * harbour/include/hbstack.h
+  * harbour/include/hbvmpub.h
+  * harbour/include/hbtypes.h
+  * harbour/src/vm/estack.c
+  * harbour/src/vm/hvmall.c
+    * slightly modified the names of HB_{API|STACK}_MACROS.
+      These are internal macros in current Harbour code but they are
+      still defined in some old user build scripts used to compiled
+      user or core code what could cause unpredictable results for
+      final binaries. AFAIR default xMate configuration enables them.
+
 2010-05-24 11:02 UTC+0200 Viktor Szakats (harbour.01 syenar.hu)
   * utils/hbmk2/hbmk2.prg
     ! Fixed non-initialized variable (broken in after one of
diff --git a/harbour/include/hbapi.h b/harbour/include/hbapi.h
index c8380061a2..7ffc4c8d59 100644
--- a/harbour/include/hbapi.h
+++ b/harbour/include/hbapi.h
@@ -699,7 +699,7 @@ extern HB_EXPORT void   hb_retnlllen( HB_LONGLONG lNumber, int iWidth ); /* retu
 
 #define HB_IS_VALID_INDEX( idx, max )  ( (idx) > 0 && ( HB_ULONG ) (idx) <= (max) )
 
-#ifdef HB_API_MACROS
+#ifdef _HB_API_MACROS_
 
 #define hb_pcount()                          ( ( int ) ( hb_stackBaseItem() )->item.asSymbol.paramcnt )
 
@@ -731,7 +731,7 @@ extern HB_EXPORT void   hb_retnlllen( HB_LONGLONG lNumber, int iWidth ); /* retu
 #define hb_retptr( pointer )                 hb_itemPutPtr( hb_stackReturnItem(), pointer )
 #define hb_retptrGC( pointer )               hb_itemPutPtrGC( hb_stackReturnItem(), pointer )
 
-#endif /* HB_API_MACROS */
+#endif /* _HB_API_MACROS_ */
 
 
 extern HB_EXPORT int    hb_stor( int iParam ); /* stores a NIL on a variable by reference */
@@ -1047,9 +1047,9 @@ extern void       hb_memvarRestoreFromArray( PHB_ITEM pArray );
 extern void       hb_memvarValueIncRef( PHB_ITEM pValue ); /* increase the reference count of a global value */
 extern void       hb_memvarValueDecRef( PHB_ITEM pValue ); /* decrease the reference count of a global value */
 extern PHB_ITEM   hb_memvarGetItem( PHB_SYMB pMemvarSymb );
-#if defined( HB_API_MACROS )
+#if defined( _HB_API_MACROS_ )
 #  define hb_memvarValueIncRef( p )       hb_xRefInc( p )
-#endif /* HB_API_MACROS */
+#endif /* _HB_API_MACROS_ */
 #endif /* _HB_API_INTERNAL_ */
 
 /* console I/O subsystem */
diff --git a/harbour/include/hbstack.h b/harbour/include/hbstack.h
index bd14b01408..a560a4c3f7 100644
--- a/harbour/include/hbstack.h
+++ b/harbour/include/hbstack.h
@@ -188,10 +188,10 @@ typedef struct
 #endif
 } HB_STACK, * PHB_STACK;
 
-#if defined( HB_STACK_MACROS )
+#if defined( _HB_STACK_MACROS_ )
 #  if defined( HB_MT_VM )
 #     if defined( HB_USE_TLS )
-#        if !defined( HB_STACK_LOCAL_MACROS )
+#        if !defined( _HB_STACK_LOCAL_MACROS_ )
 #           if defined( __BORLANDC__ )
                extern PHB_STACK HB_TLS_ATTR hb_stack_ptr;
 #           else
@@ -199,13 +199,13 @@ typedef struct
 #           endif
 #        endif
 #     else
-#        if !defined( HB_STACK_LOCAL_MACROS )
+#        if !defined( _HB_STACK_LOCAL_MACROS_ )
             extern HB_TLS_KEY hb_stack_key;
 #        endif
 #        if defined( __BORLANDC__ ) && defined( HB_STACK_PRELOAD ) && \
             !defined( HB_OS_WIN_64 ) && !defined( HB_OS_WIN_CE ) && \
             defined( HB_ASM_TLS )
-#           if defined( HB_STACK_LOCAL_MACROS )
+#           if defined( _HB_STACK_LOCAL_MACROS_ )
                static HB_TLS_KEY hb_stack_key;
 #           endif
             static __inline void * hb_stack_ptr_from_tls( void )
@@ -222,7 +222,7 @@ typedef struct
 #           define hb_stack_ptr_get()    hb_stack_ptr_from_tls()
 #        elif defined( __MINGW32__ ) && defined( HB_ASM_TLS ) && \
               !defined( HB_OS_WIN_64 ) && !defined( HB_OS_WIN_CE )
-#           if defined( HB_STACK_LOCAL_MACROS )
+#           if defined( _HB_STACK_LOCAL_MACROS_ )
                static HB_TLS_KEY hb_stack_key;
 #           endif
             static __inline__  __attribute__ ((pure, malloc)) void * hb_stack_ptr_from_tls( void )
@@ -257,7 +257,7 @@ typedef struct
 #        define hb_stack_ref()      ( hb_stack_ptr )
 #     endif
 #  else
-#     if !defined( HB_STACK_LOCAL_MACROS )
+#     if !defined( _HB_STACK_LOCAL_MACROS_ )
          extern HB_STACK hb_stack;
 #     endif
 #     define hb_stack_ref()         ( &hb_stack )
@@ -267,7 +267,7 @@ typedef struct
 #  if defined( HB_STACK_PRELOAD )
 #     define HB_STACK_TLS_PRELOAD
 #     undef  HB_STACK_PRELOAD
-#  elif defined( HB_STACK_MACROS )
+#  elif defined( _HB_STACK_MACROS_ )
 #     define HB_STACK_TLS_PRELOAD
 #  endif
 #endif
@@ -376,7 +376,7 @@ extern void        hb_stackUpdateAllocator( void *, PHB_ALLOCUPDT_FUNC, int );
 #endif
 
 
-#if defined( HB_STACK_MACROS )
+#if defined( _HB_STACK_MACROS_ )
 
 #define hb_stackItemFromTop( n )    ( * ( hb_stack.pPos + ( int ) ( n ) ) )
 #define hb_stackItemFromBase( n )   ( * ( hb_stack.pBase + ( int ) ( n ) + 1 ) )
diff --git a/harbour/include/hbtypes.h b/harbour/include/hbtypes.h
index 5dd559dcf4..39e6159ee5 100644
--- a/harbour/include/hbtypes.h
+++ b/harbour/include/hbtypes.h
@@ -53,7 +53,7 @@
 #ifndef HB_TYPES_H_
 #define HB_TYPES_H_
 
-#undef HB_API_MACROS
+#undef _HB_API_MACROS_
 
 #include "hbapi.h"
 
diff --git a/harbour/include/hbvmint.h b/harbour/include/hbvmint.h
index bc7df447a4..03795616e1 100644
--- a/harbour/include/hbvmint.h
+++ b/harbour/include/hbvmint.h
@@ -59,8 +59,8 @@
  * which interacts with alignment are used. [druzus]
  */
 
-#undef HB_API_MACROS
-#undef HB_STACK_MACROS
+#undef _HB_API_MACROS_
+#undef _HB_STACK_MACROS_
 
 #if !defined( _HB_API_INTERNAL_ )
 #  define _HB_API_INTERNAL_
diff --git a/harbour/include/hbvmopt.h b/harbour/include/hbvmopt.h
index 38a136c533..c1874f749d 100644
--- a/harbour/include/hbvmopt.h
+++ b/harbour/include/hbvmopt.h
@@ -58,12 +58,12 @@
  * it was compiled and only if exactly the same C compiler switches
  * which interacts with alignment are used. [druzus]
  */
-#if !defined( HB_NO_DEFAULT_API_MACROS ) && !defined( HB_API_MACROS )
-#  define HB_API_MACROS
+#if !defined( HB_NO_DEFAULT_API_MACROS ) && !defined( _HB_API_MACROS_ )
+#  define _HB_API_MACROS_
 #endif
 
-#if !defined( HB_NO_DEFAULT_STACK_MACROS ) && !defined( HB_STACK_MACROS )
-#  define HB_STACK_MACROS
+#if !defined( HB_NO_DEFAULT_STACK_MACROS ) && !defined( _HB_STACK_MACROS_ )
+#  define _HB_STACK_MACROS_
 #endif
 
 #if !defined( _HB_API_INTERNAL_ )
diff --git a/harbour/include/hbvmpub.h b/harbour/include/hbvmpub.h
index 097a7c9b83..a19e34c10b 100644
--- a/harbour/include/hbvmpub.h
+++ b/harbour/include/hbvmpub.h
@@ -157,8 +157,8 @@ struct _HB_SYMB;
 
 #else /* !_HB_API_INTERNAL_ */
 
-#  undef HB_API_MACROS
-#  undef HB_STACK_MACROS
+#  undef _HB_API_MACROS_
+#  undef _HB_STACK_MACROS_
 
 /* This is ugly trick but works without speed overhead */
 #  define HB_ITEM_TYPERAW( p )   ( * ( HB_TYPE * ) ( p ) )
diff --git a/harbour/src/vm/estack.c b/harbour/src/vm/estack.c
index f3dd14f6c5..ce290b6405 100644
--- a/harbour/src/vm/estack.c
+++ b/harbour/src/vm/estack.c
@@ -87,13 +87,13 @@
 #  ifdef HB_USE_TLS
 
       /* compiler has native support for TLS */
-#     if !defined( HB_STACK_MACROS )
+#     if !defined( _HB_STACK_MACROS_ )
 #        if defined( __BORLANDC__ )
             static PHB_STACK HB_TLS_ATTR hb_stack_ptr;
 #        else
             static HB_TLS_ATTR PHB_STACK hb_stack_ptr;
 #        endif
-#     elif !defined( HB_STACK_LOCAL_MACROS )
+#     elif !defined( _HB_STACK_LOCAL_MACROS_ )
 #        if defined( __BORLANDC__ )
             PHB_STACK HB_TLS_ATTR hb_stack_ptr = NULL;
 #        else
@@ -110,10 +110,10 @@
 #  else
 
       /* compiler has no native TLS support, we have to implement it ourselves */
-#     if !defined( HB_STACK_MACROS )
+#     if !defined( _HB_STACK_MACROS_ )
          static HB_TLS_KEY hb_stack_key;
 #        define hb_stack_ptr     ( ( PHB_STACK ) hb_tls_get( hb_stack_key ) )
-#     elif !defined( HB_STACK_LOCAL_MACROS )
+#     elif !defined( _HB_STACK_LOCAL_MACROS_ )
          HB_TLS_KEY hb_stack_key;
 #     endif
       static volatile HB_BOOL s_fInited = HB_FALSE;
@@ -138,9 +138,9 @@
 #else
 
    /* no MT mode */
-#  if !defined( HB_STACK_MACROS )
+#  if !defined( _HB_STACK_MACROS_ )
       static HB_STACK hb_stack;
-#  elif !defined( HB_STACK_LOCAL_MACROS )
+#  elif !defined( _HB_STACK_LOCAL_MACROS_ )
       HB_STACK hb_stack;
 #  endif
 
diff --git a/harbour/src/vm/hvmall.c b/harbour/src/vm/hvmall.c
index 0f5abe96b7..010f175c34 100644
--- a/harbour/src/vm/hvmall.c
+++ b/harbour/src/vm/hvmall.c
@@ -58,7 +58,7 @@
 
 #define HB_NO_FLATTEN
 
-#define HB_STACK_LOCAL_MACROS
+#define _HB_STACK_LOCAL_MACROS_
 #define HB_STACK_PRELOAD
 
 #define INCL_BASE
@@ -84,7 +84,7 @@
 
 #include "hbstack.h"
 
-#if defined( HB_STACK_MACROS ) && defined( HB_STACK_LOCAL_MACROS )
+#if defined( _HB_STACK_MACROS_ ) && defined( _HB_STACK_LOCAL_MACROS_ )
 #  if defined( HB_MT_VM )
 #     if defined( HB_USE_TLS )
 #        if defined( __BORLANDC__ )