cross compilation for unix on windows/mingw should work

Trying to compile Qt5.2.1 for linux cross compilation on Windows/mingw32.

The build fails in many ways. This is clearly a problem many people have, cf:
http://qt-project.org/forums/viewthread/37298/
http://c2143.blogspot.fr/2011/08/developping-for-qt-48-embedded-on.html

I don't see it fixed in git, but maybe I'm wrong.

I setup a new mkspec for my platform linux-arm-gnueabihf-win32g++.
My batch file setup the paths and call configure.bat with correct parameters.

0. The generic linux-arm-gnueabi-g++ mkspec don't autodetect we are compiling on Windows.
So we have to include(../common/shell-win32.conf) in qmake.conf.
Well, OK, but this one took me some time to find...

1. First try with MAKEFILE_GENERATOR = MINGW
After "Running configuration tests...", we have an error: [...]ld.exe: cannot find ./arch.obj
The makefile are not generated, see "generator-mingw.log"

2. First try with MAKEFILE_GENERATOR = UNIX
make reports errors in a makefile about "{", "DESTDIR" and "true" beeing unknown commands.

but in the end, the makefile is generated.

3. When building

global\qlibraryinfo.cpp:363:20: error: 'QT_CONFIGURE_SETTINGS_PATH' was not declared in this scope
path = QT_CONFIGURE_SETTINGS_PATH;

see "generator-unix.log"

Some users fixed it and report further errors:
thread\qwaitcondition_unix.cpp: In function 'void qt_initialize_pthread_cond(pthread_cond_t*, const char*)':
thread\qwaitcondition_unix.cpp:83:61: error: 'pthread_condattr_setclock' was not declared in this scope

Can you fix these ?

PS: make confclean still does not work !
this is really painful when we want to rebuild...