Fix build failures on some architectures
- linux-perf: Add libtraceevent-dev to Build-Depends (fixes FTBFS on s390x, sh4, sparc64, and others)
- [hppa] Delete redundant register definitions in <asm/assembly.h> (fixes FTBFS)
- [m68k] Fix invalid .section syntax (fixes FTBFS)
Also fix all the bugs that blocked me from cross-building hppa.
Edited by Ben Hutchings