The linux-libc-headers (llh) package (available at http://ep09.pld-linux.org/~mmazur/linux-libc-headers/) contains headers that export linux abi to userspace. These headers are a heavily modified and cleaned up version of what comes with original linux tarball. See the FAQ for more details. Userland usefulness is achieved by removing kernel only parts (which often generate errors) and using code provided by libc where possible (this allows to avoid collisions when both linux and libc headers define the same structure or constant). Unfortunately libc dependency might result in functionality loss since libcs aren't always in sync with what kernel provides. If such a case occurs please send a bug report to the maintainer (see AUTHORS file) and, if possible, a workaround will be added. Do note that since llh is primarily for 2.6 based kernels we assume glibc to be at least version 2.3.3 (as far as I know this version wasn't released officially but is being used by many current linux distributions). Glibc is not a requirement though - llh is known to work with other implementations of standard C library - but obviously is a priority, so be prepared to send a bugreport if using something else. In case you're wondering why take such an approach if it's obvious that it might generate problems. Well, according to my knowledge there is consensus among kernel hackers as to how userland headers should look like, but unfortunately proper implementation (and wider adoption) will take time and something that just plain works (in most cases anyway) is needed now.