We need to put ourself back in wait mode after every loop iteration,
otherwise a spurious wakeup can result in the predicate returning false,
and then we will never wait again, instead spinning endlessly.

'osv thread' mucks around cpu registers, restore them before resuming the
guest.

This command allows the developer to switch to and examine an osv thread.

Fail the build if not.

Pack the mutex by placing small fields next to each other.  This fixes
sizeof(cond_var) becoming larger than sizeof(pthread_cond_t), and corrupting
memory.

Detect running threads by checking whether any cpu's rsp is within the thread
stack.  If so, the thread is running on that cpu, and the saved context is
ignored as stale.  This improves 'osv info threads' greatly.

It doesn't work all that well for threads taking interrupts though.

We'll collect more osv state there.

(but don't wait for it)

* 'master' of github.com:cloudius-systems/osv:
  apic: mask LVT0 interrupts
  x64: load IDT on non-boot processors
  apic: software-enable the APIC on non-boot processors
  libc: import setjmp/longjmp from musl
  build: rule for compiling .s files
  make printf print directly onto the console before the VFS is up
  update glibc-testsuite

This avoids spurious interrupts from the PIC (even though it has been
disabled).

reduce the verbosity

Needed by bench.jar suddenly.

For musl code.

* 'master' of github.com:cloudius-systems/osv:
  sched: fix race between stop_wait() and wake()
  split the test runner into a separate object
  rename main to osv_main in the payload
  shut up mallopt
  sched: poll wakeups during yield
  gdb: fix exceptions when a thread function/file cannot be decoded
  sched: load balance threads on cpus
  sched: fix _on_runqueue not set during wakeup
  sched: explicity request the runqueue to have constant-time size
  sched: defer thread stack allocation
  smp: mark smp bringup threads as pinned
  sched: add 'pinned' attribute to threads
  sched: clear timer expired flag when re-arming timer
  Remove clock_event test
  mutex: fairness
  main: test clock events earlier