Adding event logging to libc.

I've basically just copied the relevant bits out of liblog and
EventLog.cpp. While this will let us do the uid logging we want
to address the concerns in 245c07027f78565858dd489eb0d94c3d48743e9d
it doesn't give us much else.

Change-Id: Icac6ff20bc0a3ade5927f6f76fedffe1ae6f8522
2 files changed