Workaround for gcc volatile struct member bug

gcc does not handle struct with volatile member assignments correctly.
See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47409

Using structure assignments for the StateAndFlag union can cause gcc
to optimise the code incorrectly. Doing the assignment using the
as_int member forces the correct behaviour.

Change-Id: I6379d36add16c321b2e4d1dcd6fd8c959f3f92d6

Conflicts:
	runtime/thread-inl.h
	runtime/thread.cc
Enable building ART with clang

Change-Id: I36bf66a90dfc03d27e2888d24d074a37fdac67d3

Fix compile error and silence the chatty ART if it is built with clang

Change-Id: Ia23c95fc56d0334622f0ff1e59ed7d579af16211
Fix build.
Reduce logging verbosity by default to ERROR

This is probably not the best way to disable logging spam. It'll be changed if there is a better solution.

Change-Id: Ie4af4a8897c109c364ea65745c55105c6d88485b