./autogen.sh --prefix /gnome/usr --libdir '/gnome/usr/lib' --disable-static --disable-gtk-doc
aclocal: couldn't open directory `m4': Aucun fichier ou dossier de ce type
autoreconf: aclocal failed with exit status: 1
autogen.sh should create the m4 subdirectory, or we should have a m4/.gitignore file in git to make sure hte m4 directory exists after a fresh clone.
I think this was fixed some time ago by commit 3d74d256377a94864d06994924ae629dbf76dfda