Me again, sorry, need to add something important :

kdelibs/nana/L.h contains :

#ifndef __GNUC__
error you need gcc for this stuff to work properly
#endif


Doesn't KDE compile with other compilers than gcc ? IIRC Stephan and others
mentionned it did.
Well it doesn't anymore. :(((

The sad thing is that this restriction seems related to macros with
var args (can anybody confirm that ?), so kdebug won't be able to show 
file and line either, except if we switch to
kDebug(QString("...").arg(...).arg(...)) 
(ouch!) to avoid var args. Then we can define kDebug as a macro, calling a
function with __FILE__,__LINE__ as first args.

In short, nana and kdebug have the same problem (for the line and file
stuff) :
either they can do it and that limits KDE to gcc, or they can't.
:(