After Fedora rebuild kBuild with gcc 4.7, kmk_sed doesn't work correctly. I reported upstream http://svn.netlabs.org/kbuild/ticket/112 . I couldn't find any solution, but I found one workaround which is use kBuild bundle in VirtualBox. May I do this exception until we find what happen to kBuild compiled with gcc-4.7 ? Note 1: I think kBuild will not have a different behavior. Note 2: I like update VirtualBox on F17 and rawhide on move on testing with new X11 version etc . I have done a Mesa patch or un-bundle more X11 sources. Thanks, -- Sérgio M. B.