Use pthread_mach_thread_np(pthread_self()) instead of mach_thread_self()

Use pthread_mach_thread_np(pthread_self()) instead of mach_thread_self().

mach_thread_self() needs to be balanced by mach_port_deallocate(), which is
two system calls. The existing uses of mach_thread_self() were not
deallocated, which was a bug. pthread_mach_thread_np(pthread_self()) is two
libc function calls and no system calls, because pthread caches the Mach port.
When using pthread's cached port, no mach_port_deallocate() is necessary (it
would be an error to deallocate).

Additional background is available in http://crbug.com/105513 .

R=mseaborn@chromium.org

Committed: https://src.chromium.org/viewvc/native_client?view=rev&revision=13165

[Mark Mentovai, 2014-05-09 19:40:59]

http://crbug.com/105513 has some additional background. The same strategy is
used in trusted/service_runtime/osx/mach_thread_map.c since NaCl r10861
(https://codereview.chromium.org/12207165).

[Mark Seaborn, 2014-05-09 19:46:52]

LGTM, thanks

On 2014/05/09 19:40:59, Mark Mentovai wrote:
> http://crbug.com/105513 has some additional background.

Can you reference that issue in the commit message, please?

[Mark Mentovai, 2014-05-09 20:34:12]

Committed patchset #1 manually as r13165 (presubmit successful).