add client thread synchronization support: condition variables in particular

From [email protected] on April 01, 2010 14:49:29

issue #41 (closed) adds client threads but there is no synch support other than DR locks. there are issues with client threads interacting with DR's synchall so we need to make sure we provide solutions that have good safe spots and work well with synchall (xref PR 231301).

Original issue: http://code.google.com/p/dynamorio/issues/detail?id=279