BUILD SYSTEM: Ubuntu gutsy
STATUS: Works

REQUIRE: 
 - Bacula cross compilation tool (must be able to compile bacula-fd.exe)
 - wine (apt-get install wine)
 - qt mingw32 distribution

ORIGINAL HOWTO (french):
http://doc.qtfr.org/post/2007/04/10/Cross-Compilation-Native-dapplication-Qt-depuis-Linux

Legend:
# comment
$ shell command
* tips

Directory setup
---------------
$ cd bacula/src/win32
$ ./build-win32-cross-tools
$ ./build-depkgs-mingw32

It will result something like :

./
|-- depkgs-mingw32
|-- cross-tools
`-- bacula

Linux bacula setup -- Note: I believe that this is *required* before trying
                      to build the Win32 bat.
------------
$ cd bacula
$ ./configure <your-options-for Linux>
$ cd bacula/src/win32
$ make

Make sure that bacula/src/win32/release/bacula.dll is built

QT4 setup
----------

Install QT for mingw

Get the mingw installation from http://trolltech.com/developer/downloads/qt/windows
(Try to get the same version than your linux installation)
ftp://ftp.qtsoftware.com/qt/source


$ wine qt-win-opensource-4.3.5-mingw.exe
 * Install under c:\Qt (no space)
 * no worry about mingw installation

$ cp -r ~/.wine/drive_c/Qt/4.3.5/src/    depkgs-mingw32/include
$ cp -r ~/.wine/drive_c/Qt/4.3.5/include depkgs-mingw32/include/qt
$ cp -r ~/.wine/drive_c/Qt/4.3.5/lib     depkgs-mingw32/lib/qt
# cp ~/.wine/drive_c/Qt/4.3.5/bin/QtCore4.dll src/win32/release32
# cp ~/.wine/drive_c/Qt/4.3.5/bin/QtGui4.dll src/win32/release32

MINGW setup
-----------
I think this only needs to be done once ...

--- cross-tools/mingw32/mingw32/include/wchar.h.org     2008-07-13 15:18:52.000000000 +0200
+++ cross-tools/mingw32/mingw32/include/wchar.h 2008-07-12 14:47:10.000000000 +0200
@@ -394,7 +394,7 @@
        time_t  st_ctime;       /* Creation time */
 };

-#ifndef _NO_OLDNAMES
+#ifdef _NO_OLDNAMES_DISABLE
 /* NOTE: Must be the same as _stat above. */
 struct stat
 {

Compile bat
-----------

$ cd bacula/src/qt-console
$ export DEPKGS="directory above cross-tools and depkgs"
$ ./make-win32 clean
$ ./make-win32

Cleanup
-------
$ cd bacula/src/qt-console
$ ./make-win32 clean

The bat.exe will be in src/qt-console/debug/bat.exe



Run Bat on Windows
------------------

You'll need
   zlib1.dll
   ssleay32.dll
   libeay32.dll
   QtCore4.dll
   QtGui4.dll
   bacula.dll
   pthreadGCE.dll
   mingwm10.dll
   bat.conf

You can find the Qt dlls in ~/.wine/drive_c/Qt/4.3.5/bin

Run Bat with wine
-----------------
$ cd bacula/src/qt-console/debug

# configure a bat.conf
# copy all dlls to this directory

$ wine bat 


That all, easy isn't it ?