add support for SYS_timerfd_create

From bruen...@google.com on April 07, 2013 13:21:02

The linux kernel had some features added "recently" (relative to DR's signal handling implementation :)), in 2007 in the 2.6.22 kernel, that DR needs to handle because DR emulates that part of the kernel. signalfd ( issue #1138 (closed) ) is one of them, and timerfd (this issue) is another.

Original issue: http://code.google.com/p/dynamorio/issues/detail?id=1139