Changeset 0f6a3015:
"perf tools: Support user regs and stack in sample parsing"

uses hweight_long in evsel.c, so we need to drag util/hweight.c
to the python binding.

Ditto for ee8dd3ca:
"perf tools: Change strlist to use the new rblist"

where we need to add util/rblist.c.

Now twatch.py works again:

 # export PYTHONPATH=~acme/git/build/perf/python/
 # ~acme/git/linux/tools/perf/python/twatch.py
 cpu:  4, pid: 23639, tid: 23639 { type: fork, pid: 30659, ppid: 23639, tid: 30659, ptid: 23639, time: 36287872076780}
 cpu:  5, pid: 30659, tid: 30659 { type: comm, pid: 30659, tid: 30659, comm: ls }
 cpu:  5, pid: 30659, tid: 30659 { type: exit, pid: 30659, ppid: 30659, tid: 30659, ptid: 30659, time: 36287873681539}
 cpu:  4, pid: 23639, tid: 23639 { type: fork, pid: 30660, ppid: 23639, tid: 30660, ptid: 23639, time: 36291720420480}
 cpu:  5, pid: 30659, tid: 30659 { type: exit, pid: 30659, ppid: 30659, tid: 30659, ptid: 30659, time: 36287873685714}
 c...