flock, vdso, rt_sigtimedwait, signalfd

signalfd(2) support (#1048)

support for signalfd(2)

* The notify_set has uses outside of the context of poll waiters. In order to use it for signalfd notifications, the eventmask was expanded to 64-bits.
* State and events for fds (fdescs) were previously process-wide. However a signalfd, which may be used in any thread in a process, may reflect state that is specific to a particular thread (e.g. for a signal that is delivered at the thread (not thread group / process) level). As such, the poll waiters now specify the blocking thread when checking for fdesc events. event_handlers also now take an optional thread argument so that posted events are only relevant if the collecting waiter is blocked on behalf of the specified thread.
* sigstate_flush_queue was broken, causing an assertion failure if a thread exited without handling all pending signals

perf improvements, arg0 fixes; initial ftrace, js fixes

cpuid check for rdseed/rdrand on init only (#1013)

* cpuid check for rdseed/rdrand on init only

* explicit initializations

initial t2 support

0.1.20

trivial: mmap runtime test was missing from runtime-tests rule (#976)

capset/caget stubs; sendfile fixes; table log fixes; sigsegv;

SIGSEGV support. Includes: (#964)

* SIGSEGV support. Includes:
 - raise SIGSEGV from mmap fault handler
 - add ucontext save/restore to signal delivery/return code
 - update signal runtime test with SIGSEGV test

* bugfix for sig_debug call in rt_sigreturn

* some reorganization of page fault handler, and bugfix for
field ordering in struct sigcontext

* add CR2 to frame.h, and save on interrupt

* send SEGV_MAPERR anytime we can't find a vmap on fault

initial signals; monotonic; readv/writev

getsockopt(2): add stub handler for SO_SNDBUF

This is needed by Vert.x (ticket #824).

Closes #853.