diff --git a/harbour/ChangeLog b/harbour/ChangeLog
index 996f984487..d00f55647a 100644
--- a/harbour/ChangeLog
+++ b/harbour/ChangeLog
@@ -16,6 +16,45 @@
    The license applies to all entries newer than 2009-04-28.
 */
 
+2011-01-14 10:12 UTC+0100 Przemyslaw Czerpak (druzus/at/priv.onet.pl)
+  * harbour/config/beos/gcc.mk
+  * harbour/config/qnx/gcc.mk
+  * harbour/config/bsd/gcc.mk
+  * harbour/config/wce/mingwarm.mk
+  * harbour/config/vxworks/gcc.mk
+  * harbour/config/hpux/gcc.mk
+  * harbour/config/darwin/gcc.mk
+  * harbour/config/dos/djgpp.mk
+  * harbour/config/win/mingw.mk
+  * harbour/config/linux/gcc.mk
+  * harbour/config/cygwin/gcc.mk
+  * harbour/config/symbian/gcc.mk
+  * harbour/config/os2/gcc.mk
+  * harbour/config/sunos/gcc.mk
+    * use -Wall -Wno-unused -Wno-pointer-sign -Wno-uninitialized
+          -Wno-switch -Wno-strict-overflow -Wno-main
+      instead of -W when warnings are not enabled with GCC based compilers.
+      Using only -W only is rather useless because this switch enables
+      warnings which can be usually ignored in 3-rd party code.
+      This modification should help in locating bugs introduced by us
+      to 3-rd party code, i.e. due to wrong header files used on some
+      platforms (we do not use autoconf assuming some default settings
+      what can be wrong in some cases). It should also not hide some
+      important/critical bugs in 3-rd party code.
+      This modification pacifies some common warnings which can be
+      ignored usually but it also enables some more important ones.
+      If it's necessary then we can tune it a little bit more and disable
+      some other warnings too.
+      It's possible that on some platforms using very old GCC versions
+      some of -W* switches are not supported - please make tests and
+      inform us about problems.
+
+  * harbour/utils/hbmk2/hbmk2.prg
+    * use -Wall -Wno-unused -Wno-pointer-sign -Wno-uninitialized
+          -Wno-switch -Wno-strict-overflow -Wno-main
+      instead of -W when warning level is set to low with GCC based
+      compilers
+
 2011-01-14 08:35 UTC+0100 Przemyslaw Czerpak (druzus/at/priv.onet.pl)
   * harbour/include/hbdefs.h
     * use native stdint.h for MSVC 2010. Patch by Andi, thx.
diff --git a/harbour/config/beos/gcc.mk b/harbour/config/beos/gcc.mk
index 229aa6ac13..a9284e4675 100644
--- a/harbour/config/beos/gcc.mk
+++ b/harbour/config/beos/gcc.mk
@@ -23,7 +23,7 @@ CFLAGS += -I. -I$(HB_HOST_INC)
 ifneq ($(HB_BUILD_WARN),no)
    CFLAGS += -W -Wall
 else
-   CFLAGS += -W
+   CFLAGS += -Wall -Wno-unused -Wno-pointer-sign -Wno-uninitialized -Wno-switch -Wno-strict-overflow -Wno-main
 endif
 
 ifneq ($(HB_BUILD_OPTIM),no)
diff --git a/harbour/config/bsd/gcc.mk b/harbour/config/bsd/gcc.mk
index 33c7df1253..bc59b6fa6f 100644
--- a/harbour/config/bsd/gcc.mk
+++ b/harbour/config/bsd/gcc.mk
@@ -25,7 +25,7 @@ CFLAGS += -I. -I$(HB_HOST_INC)
 ifneq ($(HB_BUILD_WARN),no)
    CFLAGS += -W -Wall
 else
-   CFLAGS += -W
+   CFLAGS += -Wall -Wno-unused -Wno-pointer-sign -Wno-uninitialized -Wno-switch -Wno-strict-overflow -Wno-main
 endif
 
 ifneq ($(HB_BUILD_OPTIM),no)
diff --git a/harbour/config/cygwin/gcc.mk b/harbour/config/cygwin/gcc.mk
index 3602e33c5b..2cf6fa1605 100644
--- a/harbour/config/cygwin/gcc.mk
+++ b/harbour/config/cygwin/gcc.mk
@@ -21,7 +21,7 @@ CFLAGS += -I. -I$(HB_HOST_INC)
 ifneq ($(HB_BUILD_WARN),no)
    CFLAGS += -W -Wall
 else
-   CFLAGS += -W
+   CFLAGS += -Wall -Wno-unused -Wno-pointer-sign -Wno-uninitialized -Wno-switch -Wno-strict-overflow -Wno-main
 endif
 
 ifneq ($(HB_BUILD_OPTIM),no)
diff --git a/harbour/config/darwin/gcc.mk b/harbour/config/darwin/gcc.mk
index 548991ac8f..8b7c96b3c2 100644
--- a/harbour/config/darwin/gcc.mk
+++ b/harbour/config/darwin/gcc.mk
@@ -31,7 +31,7 @@ CFLAGS += -fno-common
 ifneq ($(HB_BUILD_WARN),no)
    CFLAGS += -W -Wall
 else
-   CFLAGS += -W
+   CFLAGS += -Wall -Wno-unused -Wno-pointer-sign -Wno-uninitialized -Wno-switch -Wno-strict-overflow -Wno-main
 endif
 
 ifneq ($(HB_BUILD_OPTIM),no)
diff --git a/harbour/config/dos/djgpp.mk b/harbour/config/dos/djgpp.mk
index 1e446ed9c1..d0da345b17 100644
--- a/harbour/config/dos/djgpp.mk
+++ b/harbour/config/dos/djgpp.mk
@@ -22,7 +22,7 @@ CFLAGS += -I. -I$(HB_HOST_INC)
 ifneq ($(HB_BUILD_WARN),no)
    CFLAGS += -W -Wall
 else
-   CFLAGS += -W
+   CFLAGS += -Wall -Wno-unused -Wno-pointer-sign -Wno-uninitialized -Wno-switch -Wno-strict-overflow -Wno-main
 endif
 
 ifneq ($(HB_BUILD_OPTIM),no)
diff --git a/harbour/config/hpux/gcc.mk b/harbour/config/hpux/gcc.mk
index 0a9b30d846..83d88a708b 100644
--- a/harbour/config/hpux/gcc.mk
+++ b/harbour/config/hpux/gcc.mk
@@ -27,7 +27,7 @@ CFLAGS += -I. -I$(HB_HOST_INC)
 ifneq ($(HB_BUILD_WARN),no)
    CFLAGS += -W -Wall
 else
-   CFLAGS += -W
+   CFLAGS += -Wall -Wno-unused -Wno-pointer-sign -Wno-uninitialized -Wno-switch -Wno-strict-overflow -Wno-main
 endif
 
 ifneq ($(HB_BUILD_OPTIM),no)
diff --git a/harbour/config/linux/gcc.mk b/harbour/config/linux/gcc.mk
index 33c7df1253..bc59b6fa6f 100644
--- a/harbour/config/linux/gcc.mk
+++ b/harbour/config/linux/gcc.mk
@@ -25,7 +25,7 @@ CFLAGS += -I. -I$(HB_HOST_INC)
 ifneq ($(HB_BUILD_WARN),no)
    CFLAGS += -W -Wall
 else
-   CFLAGS += -W
+   CFLAGS += -Wall -Wno-unused -Wno-pointer-sign -Wno-uninitialized -Wno-switch -Wno-strict-overflow -Wno-main
 endif
 
 ifneq ($(HB_BUILD_OPTIM),no)
diff --git a/harbour/config/os2/gcc.mk b/harbour/config/os2/gcc.mk
index e8de6394f5..5cdb5c6b13 100644
--- a/harbour/config/os2/gcc.mk
+++ b/harbour/config/os2/gcc.mk
@@ -30,7 +30,7 @@ endif
 ifneq ($(HB_BUILD_WARN),no)
    CFLAGS += -W -Wall
 else
-   CFLAGS += -W
+   CFLAGS += -Wall -Wno-unused -Wno-pointer-sign -Wno-uninitialized -Wno-switch -Wno-strict-overflow -Wno-main
 endif
 
 ifneq ($(HB_BUILD_OPTIM),no)
diff --git a/harbour/config/qnx/gcc.mk b/harbour/config/qnx/gcc.mk
index 44b5d5a63b..b480a90433 100644
--- a/harbour/config/qnx/gcc.mk
+++ b/harbour/config/qnx/gcc.mk
@@ -25,7 +25,7 @@ CFLAGS += -I. -I$(HB_HOST_INC)
 ifneq ($(HB_BUILD_WARN),no)
    CFLAGS += -W -Wall
 else
-   CFLAGS += -W
+   CFLAGS += -Wall -Wno-unused -Wno-pointer-sign -Wno-uninitialized -Wno-switch -Wno-strict-overflow -Wno-main
 endif
 
 ifneq ($(HB_BUILD_OPTIM),no)
diff --git a/harbour/config/sunos/gcc.mk b/harbour/config/sunos/gcc.mk
index 17bae80e3a..61bedee631 100644
--- a/harbour/config/sunos/gcc.mk
+++ b/harbour/config/sunos/gcc.mk
@@ -25,7 +25,7 @@ CFLAGS += -I. -I$(HB_HOST_INC)
 ifneq ($(HB_BUILD_WARN),no)
    CFLAGS += -W -Wall
 else
-   CFLAGS += -W
+   CFLAGS += -Wall -Wno-unused -Wno-pointer-sign -Wno-uninitialized -Wno-switch -Wno-strict-overflow -Wno-main
 endif
 
 ifneq ($(HB_BUILD_OPTIM),no)
diff --git a/harbour/config/symbian/gcc.mk b/harbour/config/symbian/gcc.mk
index 6db85921d7..3fd3828903 100644
--- a/harbour/config/symbian/gcc.mk
+++ b/harbour/config/symbian/gcc.mk
@@ -25,7 +25,7 @@ CFLAGS += -I. -I$(HB_HOST_INC)
 ifneq ($(HB_BUILD_WARN),no)
    CFLAGS += -W -Wall
 else
-   CFLAGS += -W
+   CFLAGS += -Wall -Wno-unused -Wno-pointer-sign -Wno-uninitialized -Wno-switch -Wno-strict-overflow -Wno-main
 endif
 
 ifneq ($(HB_BUILD_OPTIM),no)
diff --git a/harbour/config/vxworks/gcc.mk b/harbour/config/vxworks/gcc.mk
index f71444d3cc..006f61dd47 100644
--- a/harbour/config/vxworks/gcc.mk
+++ b/harbour/config/vxworks/gcc.mk
@@ -35,7 +35,7 @@ CFLAGS += -D_C99 -D_HAS_C9X
 ifneq ($(HB_BUILD_WARN),no)
    CFLAGS += -W -Wall
 else
-   CFLAGS += -W
+   CFLAGS += -Wall -Wno-unused -Wno-pointer-sign -Wno-uninitialized -Wno-switch -Wno-strict-overflow -Wno-main
 endif
 
 ifneq ($(HB_BUILD_OPTIM),no)
diff --git a/harbour/config/wce/mingwarm.mk b/harbour/config/wce/mingwarm.mk
index bc4c5f2163..643fdcaa73 100644
--- a/harbour/config/wce/mingwarm.mk
+++ b/harbour/config/wce/mingwarm.mk
@@ -21,7 +21,7 @@ CFLAGS += -I. -I$(HB_HOST_INC)
 ifneq ($(HB_BUILD_WARN),no)
    CFLAGS += -W -Wall
 else
-   CFLAGS += -W
+   CFLAGS += -Wall -Wno-unused -Wno-pointer-sign -Wno-uninitialized -Wno-switch -Wno-strict-overflow -Wno-main
 endif
 
 ifneq ($(HB_BUILD_OPTIM),no)
diff --git a/harbour/config/win/mingw.mk b/harbour/config/win/mingw.mk
index 5722c45b24..4004ad5b31 100644
--- a/harbour/config/win/mingw.mk
+++ b/harbour/config/win/mingw.mk
@@ -36,7 +36,7 @@ endif
 ifneq ($(HB_BUILD_WARN),no)
    CFLAGS += -W -Wall
 else
-   CFLAGS += -W
+   CFLAGS += -Wall -Wno-unused -Wno-pointer-sign -Wno-uninitialized -Wno-switch -Wno-strict-overflow -Wno-main
 endif
 
 ifneq ($(HB_BUILD_OPTIM),no)
diff --git a/harbour/utils/hbmk2/hbmk2.prg b/harbour/utils/hbmk2/hbmk2.prg
index 979f5fe7bf..7ca75ba5d5 100644
--- a/harbour/utils/hbmk2/hbmk2.prg
+++ b/harbour/utils/hbmk2/hbmk2.prg
@@ -3181,7 +3181,7 @@ FUNCTION hbmk2( aArgs, nArgTarget, /* @ */ lPause, nLevel )
             SWITCH hbmk[ _HBMK_nWARN ]
             CASE _WARN_MAX ; AAdd( hbmk[ _HBMK_aOPTC ], "-W -Wall -pedantic" ) ; EXIT
             CASE _WARN_YES ; AAdd( hbmk[ _HBMK_aOPTC ], "-W -Wall" )           ; EXIT
-            CASE _WARN_LOW ; AAdd( hbmk[ _HBMK_aOPTC ], "-W" )                 ; EXIT
+            CASE _WARN_LOW ; AAdd( hbmk[ _HBMK_aOPTC ], "-Wall -Wno-unused -Wno-pointer-sign -Wno-uninitialized -Wno-switch -Wno-strict-overflow -Wno-main" ) ; EXIT
             CASE _WARN_NO  ; AAdd( hbmk[ _HBMK_aOPTC ], "-w" )                 ; EXIT
             ENDSWITCH
          ENDIF
@@ -3427,7 +3427,7 @@ FUNCTION hbmk2( aArgs, nArgTarget, /* @ */ lPause, nLevel )
          SWITCH hbmk[ _HBMK_nWARN ]
          CASE _WARN_MAX ; AAdd( hbmk[ _HBMK_aOPTC ], "-W -Wall -pedantic" ) ; EXIT
          CASE _WARN_YES ; AAdd( hbmk[ _HBMK_aOPTC ], "-W -Wall" )           ; EXIT
-         CASE _WARN_LOW ; AAdd( hbmk[ _HBMK_aOPTC ], "-W" )                 ; EXIT
+         CASE _WARN_LOW ; AAdd( hbmk[ _HBMK_aOPTC ], "-Wall -Wno-unused -Wno-pointer-sign -Wno-uninitialized -Wno-switch -Wno-strict-overflow -Wno-main" ) ; EXIT
          CASE _WARN_NO  ; AAdd( hbmk[ _HBMK_aOPTC ], "-w" )                 ; EXIT
          ENDSWITCH
          cOpt_CompC += " {FC}"
@@ -3561,7 +3561,7 @@ FUNCTION hbmk2( aArgs, nArgTarget, /* @ */ lPause, nLevel )
          SWITCH hbmk[ _HBMK_nWARN ]
          CASE _WARN_MAX ; AAdd( hbmk[ _HBMK_aOPTC ], "-W -Wall -pedantic" ) ; EXIT
          CASE _WARN_YES ; AAdd( hbmk[ _HBMK_aOPTC ], "-W -Wall" )           ; EXIT
-         CASE _WARN_LOW ; AAdd( hbmk[ _HBMK_aOPTC ], "-W" )                 ; EXIT
+         CASE _WARN_LOW ; AAdd( hbmk[ _HBMK_aOPTC ], "-Wall -Wno-unused -Wno-pointer-sign -Wno-uninitialized -Wno-switch -Wno-strict-overflow -Wno-main" ) ; EXIT
          CASE _WARN_NO  ; AAdd( hbmk[ _HBMK_aOPTC ], "-w" )                 ; EXIT
          ENDSWITCH
          cOpt_CompC += " {FC}"
@@ -3669,7 +3669,7 @@ FUNCTION hbmk2( aArgs, nArgTarget, /* @ */ lPause, nLevel )
          SWITCH hbmk[ _HBMK_nWARN ]
          CASE _WARN_MAX ; AAdd( hbmk[ _HBMK_aOPTC ], "-W -Wall -pedantic" ) ; EXIT
          CASE _WARN_YES ; AAdd( hbmk[ _HBMK_aOPTC ], "-W -Wall" )           ; EXIT
-         CASE _WARN_LOW ; AAdd( hbmk[ _HBMK_aOPTC ], "-W" )                 ; EXIT
+         CASE _WARN_LOW ; AAdd( hbmk[ _HBMK_aOPTC ], "-Wall -Wno-unused -Wno-pointer-sign -Wno-uninitialized -Wno-switch -Wno-strict-overflow -Wno-main" ) ; EXIT
          CASE _WARN_NO  ; AAdd( hbmk[ _HBMK_aOPTC ], "-w" )                 ; EXIT
          ENDSWITCH
          cOpt_CompC += " {FC}"