Description:
------------
The PHP sysvsem implementation lacks core functionality for semaphore usage.  The missing functionality makes tasks that can commonly be solved with semaphores in other languages not possible in PHP.

Functions that that provide the following behavior should be added:

GETVAL -- Return the value of a single semaphore. (this one is really important).

GETNCNT -- Return the number of processes waiting for the value of a semaphore to increase. 

GETZCNT -- Return the number of processes waiting for the value of a particular semaphore to reach zero. 

GETPID -- Return the PID of the process that performed the last operation on the semaphore.

The flag IPC_NOWAIT should be added to sem_acquire to set the acquire has non blocking.

Expected result:
----------------
Minimum level of semaphore support that matches implementations for virtually any other programming language.