Added optional nowait argument to sem_acquire

[mbeccati]

No description provided.

[guilhermeblanco]

I'd propose instead of accepting "nowait" only, I'd use a better support and accept "until", dealing with possible cases:

• -1: Blocks and wait until lock is acquired (default for BC compat)
• 0: Exactly what your patch does, attempt to grab and if it fails, just return false (I'd remove the E_WARNING)

• 0: Acceptable time in milliseconds it would wait until consider the acquire failed

[mbeccati]

Committed to PHP-5.6 and master.

3571a68..0b648a4 PHP-5.6 -> PHP-5.6
5b82430..205b6b8 master -> master