Versions of the Beulich dwarf2 unwinder for recent Linux kernels. Based on the version in the OpenSUSE kernels. This allows to get good kernel backtraces (without "ghost entries") without requiring the frame pointer code generation penalty. Both patches should be applied. For x86 only currently. IA64 already uses an own unwinder and the other architectures use other methods. Drawback: it's slower, e.g. oprofile with callgraph processing slows down.