first patch for process-shared semaphore

[David Xu]

Alexander Kabaev wrote:
> On Thu, 24 Dec 2009 09:22:34 +0800
> David Xu <davidxu at freebsd.org> wrote:
>> libthr does not require semaphore, it implements semaphore,
>> it is easier than other ways to implement the process-shared.
>>
> Let me rephrase: I do not think semaphores belong in libthr. They
> should be either in libc or in librt.
> 
> 
OK, does others really implement semaphore in librt ?
unfortunately, the librt already requires libpthread to implement
SIGEV_THREAD.