Build LibreOffice on Mac OS X

Hi all,

I would like to get involved in development of the Mac OS X version.
But I can't build LibreOffice even after many hours of works.
At the bottom of this message, one of my procedure.
If someone could share a working procedure, many thanks by advance.

Best regards,
  Raphaël Pautasso

Documentation I followed :
https://wiki.documentfoundation.org/Development/Native_Build
https://wiki.documentfoundation.org/Development/Building_LibreOffice_with_Clang
https://bugs.freedesktop.org/show_bug.cgi?id=54070
http://www.blog.montgomerie.net/migrating-xcode-sdks
http://sfarbotka.blogspot.fr/2012/10/build-libreoffice-on-osx108-with-xcode45.html
http://wiki.openoffice.org/wiki/CPAN_install
http://www.macports.org/install.php

Tests on :
Mac OS X 10.6.8 with Xcode 3.2.6
Mac OS X 10.7 with Xcode 4.5 (clean install)

What I did for example on 10.7 :

Migrate 10.6 SDK
Install command lines tools within xcode
Install macports
sudo port -v selfupdate
sudo port install libidl +universal
sudo port install automaker doxygen grep pkgconfig

sudo perl -MCPAN -e shell
cpan[1]> install Archive::Zip
cpan[1]> quit

mkdir git
cd git
git clone git://anongit.freedesktop.org/libreoffice/core libo
cd libo/

# Hide pkg-config (on 10.7)
sudo mv /bin/pkg-config /opt/local/bin/pkg-config

Create autogen.lastrun file in source codes root directory with next content:
--disable-binfilter
--disable-build-mozilla
--disable-mozilla
--disable-odk
--disable-online-update
--disable-python
--enable-debug=cppu/ cppuhelper/ sal/ sfx2/ stoc/ sw/ toolkit/ unotools/ vcl/
--enable-epm
--with-java-target-version=1.6
--with-macosx-version-min-required=10.6
--with-max-jobs=2
--with-num-cpus=2
--without-doxygen
--without-help
--without-helppack-integration
--without-myspell-dicts
CC=clang -m32
CXX=clang++ -m32

ulimit -c unlimited

make

Then fatal error :(

:In file included from 
9/System/Library/Frameworks/CoreData.framework/Headers/NSIncrementalStore.h::9:
/System/Library/Frameworks/CoreData.framework/Headers/NSPersistentStoreRequest.h:/System/Library/Frameworks/CoreData.framework/Headers/NSPersistentStoreRequest.h18::181::In
 file included from 1 
:/Users/raphael/Desktop/git/libo/extensions/source/macosx/spotlight/OOoMetaDataParser.m :28
error: :
error: In file included from 
/Users/raphael/Desktop/git/libo/extensions/source/macosx/spotlight/OOoMetaDataParser.hduplicate 
interface definition for class 'NSObject':duplicate interface definition for class 'NSObject'20