c4e5f34bf0
Mark the lr register as undefined at the start of execution, so unwind will stop at this frame. run-backtrace-*.sh from elfutils testsuite will fail without this patch. * sysdeps/csky/abiv2/start.S: Mark lr as undefined. * sysdeps/unix/sysv/linux/csky/abiv2/clone.S: Likewise. * sysdeps/unix/sysv/linux/csky/abiv2/setcontext.S: Likewise.