[Libreoffice] Compilation failed in vcl module (warning treated as errors)

Hello,

I get this :
Compiling: vcl/source/gdi/gdimtf.cxx
/home/maryline/compile-libreoffice/libo/clone/libs-gui/vcl/source/gdi/gdimtf.cxx:296:13: 
error: prototype for 'MetaAction* 
GDIMetaFile::ReplaceAction(MetaAction*, size_t)' does not match any in 
class 'GDIMetaFile'
../../inc/vcl/gdimtf.hxx:218:21: error: candidate is: MetaAction* 
GDIMetaFile::ReplaceAction(MetaAction*, sal_uLong)
/home/maryline/compile-libreoffice/libo/clone/libs-gui/vcl/source/gdi/gdimtf.cxx:703:6: 
error: prototype for 'void GDIMetaFile::Play(OutputDevice*, const 
Point&, const Size&, sal_uLong)' does not match any in class 'GDIMetaFile'
../../inc/vcl/gdimtf.hxx:191:21: error: candidates are: void 
GDIMetaFile::Play(OutputDevice*, const Point&, const Size&, size_t)
/home/maryline/compile-libreoffice/libo/clone/libs-gui/vcl/source/gdi/gdimtf.cxx:506:6: 
error:                 void GDIMetaFile::Play(OutputDevice*, size_t)
/home/maryline/compile-libreoffice/libo/clone/libs-gui/vcl/source/gdi/gdimtf.cxx:479:6: 
error:                 void GDIMetaFile::Play(GDIMetaFile&, size_t)
cc1plus: warnings being treated as errors
/home/maryline/compile-libreoffice/libo/clone/libs-gui/vcl/source/gdi/gdimtf.cxx: 
In member function 'void GDIMetaFile::WindPrev()':
/home/maryline/compile-libreoffice/libo/clone/libs-gui/vcl/source/gdi/gdimtf.cxx:832:92: 
error: operation on 
'((GDIMetaFile*)this)->GDIMetaFile::nCurrentActionElement' may be undefined
/home/maryline/compile-libreoffice/libo/clone/libs-gui/vcl/source/gdi/gdimtf.cxx: 
At global scope:
/home/maryline/compile-libreoffice/libo/clone/libs-gui/vcl/source/gdi/gdimtf.cxx:913:11: 
error: prototype for 'sal_uLong GDIMetaFile::GetActionPos(const 
String&)' does not match any in class 'GDIMetaFile'
../../inc/vcl/gdimtf.hxx:206:21: error: candidate is: size_t 
GDIMetaFile::GetActionPos(const String&)
dmake:  Error code 1, while making '../../unxlngi6/slo/gdimtf.obj'
Retrying /home/maryline/compile-libreoffice/libo/vcl/source/gdi

and I have this in autogen.lastrun :
--enable-ext-barcode
--enable-ext-diagram
--enable-ext-google-docs
--enable-ext-hunart
--enable-ext-lightproof
--enable-ext-nlpsolver
--enable-ext-ct2n
--enable-ext-numbertext
--enable-ext-oooblogger
--enable-ext-pdfimport
--enable-ext-presenter-console
--enable-ext-presenter-minimizer
--enable-ext-report-builder
--enable-ext-scripting-beanshell
--enable-ext-scripting-javascript
--enable-ext-scripting-python
--enable-ext-typo
--enable-ext-validator
--enable-ext-watch-window
--enable-ext-wiki-publisher
--enable-dbus
--enable-graphite
--enable-evolution2
--enable-werror
--enable-debug
--enable-dbgutil
--enable-crashdump
--enable-kde4
--enable-dependency-tracking

Since I didn't fully understand how and when to use "sal_uLong" and 
"size_t"  + their implementation with 32/64 bits, I don't know how to 
fix this.

By the way, couldn't it be useful to use --enable-werror by default ?

Julien.