diff --git a/.gitattributes b/.gitattributes
index f9f1a1738d..acf7dce095 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -3244,6 +3244,7 @@ lcl/interfaces/win32/issues.xml svneol=native#text/xml
 lcl/interfaces/win32/win32callback.inc svneol=native#text/pascal
 lcl/interfaces/win32/win32debug.pp svneol=native#text/pascal
 lcl/interfaces/win32/win32def.pp svneol=native#text/pascal
+lcl/interfaces/win32/win32defines.inc svneol=native#text/plain
 lcl/interfaces/win32/win32extra.pas svneol=native#text/pascal
 lcl/interfaces/win32/win32int.pp svneol=native#text/pascal
 lcl/interfaces/win32/win32lclintf.inc svneol=native#text/pascal
diff --git a/lcl/interfaces/win32/win32defines.inc b/lcl/interfaces/win32/win32defines.inc
new file mode 100644
index 0000000000..d3c5a0d595
--- /dev/null
+++ b/lcl/interfaces/win32/win32defines.inc
@@ -0,0 +1,38 @@
+{%MainUnit win32int.pp}
+{ $Id: gtkdefines.inc 13666 2008-01-08 11:15:07Z paul $ }
+
+{*****************************************************************************
+  Centralized includefile for common win32 defines
+ *****************************************************************************
+
+ *****************************************************************************
+ *                                                                           *
+ *  This file is part of the Lazarus Component Library (LCL)                 *
+ *                                                                           *
+ *  See the file COPYING.modifiedLGPL, included in this distribution,        *
+ *  for details about the copyright.                                         *
+ *                                                                           *
+ *  This program is distributed in the hope that it will be useful,          *
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of           *
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.                     *
+ *                                                                           *
+ *****************************************************************************
+}
+
+{$IFDEF Trace}
+{$ASSERTIONS ON}
+{$ENDIF}
+
+// defining the following will print all messages as they are being handled
+// valuable for investigation of message trees / interrelations
+{ $define MSG_DEBUG}
+
+// for now, DisableWindowsUnicodeSupport
+{$DEFINE DisableWindowsUnicodeSupport}
+{$IFNDEF DisableWindowsUnicodeSupport}
+// Enable WindowsUnicodeSupport for fpc 2.2.1 and higher
+{$IFNDEF VER2_2_0}
+{$DEFINE WindowsUnicodeSupport}
+{$ENDIF VER2_2_0}
+{$ENDIF DisableWindowsUnicodeSupport}
+
diff --git a/lcl/interfaces/win32/win32int.pp b/lcl/interfaces/win32/win32int.pp
index 1ada3e933a..e728aecfe8 100644
--- a/lcl/interfaces/win32/win32int.pp
+++ b/lcl/interfaces/win32/win32int.pp
@@ -25,17 +25,10 @@
 unit Win32Int;
 
 {$mode objfpc}{$H+}{$T-}{$message warning Fix implicit pointer conversions}
+{$I win32defines.inc}
 
 interface
 
-{$IFDEF Trace}
-{$ASSERTIONS ON}
-{$ENDIF}
-
-// defining the following will print all messages as they are being handled
-// valuable for investigation of message trees / interrelations
-{ $define MSG_DEBUG}
-
 {
   When editing this unit list, be sure to keep Windows listed first to ensure
   successful compilation.
diff --git a/lcl/interfaces/win32/win32listsl.inc b/lcl/interfaces/win32/win32listsl.inc
index 84651fe610..a45f673fa6 100644
--- a/lcl/interfaces/win32/win32listsl.inc
+++ b/lcl/interfaces/win32/win32listsl.inc
@@ -1,4 +1,4 @@
-// included by win32int.pp
+{%MainUnit win32int.pp}
 
 {******************************************************************************
                                  win32listsl.inc
diff --git a/lcl/interfaces/win32/win32memostrings.inc b/lcl/interfaces/win32/win32memostrings.inc
index ff14eaf93e..11469a83b9 100644
--- a/lcl/interfaces/win32/win32memostrings.inc
+++ b/lcl/interfaces/win32/win32memostrings.inc
@@ -1,3 +1,4 @@
+{%MainUnit win32wsstdctrls.pp}
 {$IFDEF MEMOHEADER}
 type
 
diff --git a/lcl/interfaces/win32/win32proc.pp b/lcl/interfaces/win32/win32proc.pp
index 18b6bed25c..a298a27b4a 100644
--- a/lcl/interfaces/win32/win32proc.pp
+++ b/lcl/interfaces/win32/win32proc.pp
@@ -23,6 +23,7 @@
 unit win32proc;
 
 {$mode objfpc}{$H+}
+{$I win32defines.inc}
 
 interface
 
diff --git a/lcl/interfaces/win32/win32wsbuttons.pp b/lcl/interfaces/win32/win32wsbuttons.pp
index aa009a38ef..eec63cc528 100644
--- a/lcl/interfaces/win32/win32wsbuttons.pp
+++ b/lcl/interfaces/win32/win32wsbuttons.pp
@@ -23,6 +23,7 @@
 unit Win32WSButtons;
 
 {$mode objfpc}{$H+}
+{$I win32defines.inc}
 
 interface
 
diff --git a/lcl/interfaces/win32/win32wscomctrls.pp b/lcl/interfaces/win32/win32wscomctrls.pp
index fb8b0ba722..be92c90fe6 100644
--- a/lcl/interfaces/win32/win32wscomctrls.pp
+++ b/lcl/interfaces/win32/win32wscomctrls.pp
@@ -23,6 +23,7 @@
 unit Win32WSComCtrls;
 
 {$mode objfpc}{$H+}
+{$I win32defines.inc}
 
 interface
 
diff --git a/lcl/interfaces/win32/win32wscontrols.pp b/lcl/interfaces/win32/win32wscontrols.pp
index 36f740af59..642b9f0ae6 100644
--- a/lcl/interfaces/win32/win32wscontrols.pp
+++ b/lcl/interfaces/win32/win32wscontrols.pp
@@ -23,6 +23,7 @@
 unit Win32WSControls;
 
 {$mode objfpc}{$H+}
+{$I win32defines.inc}
 
 interface
 
diff --git a/lcl/interfaces/win32/win32wsdialogs.pp b/lcl/interfaces/win32/win32wsdialogs.pp
index eec6325cc3..a935d399e8 100644
--- a/lcl/interfaces/win32/win32wsdialogs.pp
+++ b/lcl/interfaces/win32/win32wsdialogs.pp
@@ -23,6 +23,7 @@
 unit Win32WSDialogs;
 
 {$mode objfpc}{$H+}
+{$I win32defines.inc}
 
 interface
 
diff --git a/lcl/interfaces/win32/win32wsextctrls.pp b/lcl/interfaces/win32/win32wsextctrls.pp
index f72fa94fc4..c9d6bbf7dd 100644
--- a/lcl/interfaces/win32/win32wsextctrls.pp
+++ b/lcl/interfaces/win32/win32wsextctrls.pp
@@ -22,6 +22,7 @@
 unit Win32WSExtCtrls;
 
 {$mode objfpc}{$H+}
+{$I win32defines.inc}
 
 interface
 
diff --git a/lcl/interfaces/win32/win32wsmenus.pp b/lcl/interfaces/win32/win32wsmenus.pp
index 0fc3d368f7..a68e6cb0e3 100644
--- a/lcl/interfaces/win32/win32wsmenus.pp
+++ b/lcl/interfaces/win32/win32wsmenus.pp
@@ -23,6 +23,7 @@
 unit Win32WSMenus;
 
 {$mode objfpc}{$H+}
+{$I win32defines.inc}
 
 interface
 
diff --git a/lcl/interfaces/win32/win32wsspin.pp b/lcl/interfaces/win32/win32wsspin.pp
index b81c076290..766384dc18 100644
--- a/lcl/interfaces/win32/win32wsspin.pp
+++ b/lcl/interfaces/win32/win32wsspin.pp
@@ -23,6 +23,7 @@
 unit Win32WSSpin;
 
 {$mode objfpc}{$H+}
+{$I win32defines.inc}
 
 interface
 
diff --git a/lcl/interfaces/win32/win32wsstdctrls.pp b/lcl/interfaces/win32/win32wsstdctrls.pp
index fd25520ccc..3829a62b76 100644
--- a/lcl/interfaces/win32/win32wsstdctrls.pp
+++ b/lcl/interfaces/win32/win32wsstdctrls.pp
@@ -23,6 +23,7 @@
 unit Win32WSStdCtrls;
 
 {$mode objfpc}{$H+}
+{$I win32defines.inc}
 
 interface