Fixed compilation error with PHP-5.6.0RC1

fixed compilation error with PHP-5.6.0RC1, but still with some tests failure.

    
    =====================================================================
    TIME END 2014-06-23 15:53:07
    
    =====================================================================
    TEST RESULT SUMMARY
    ---------------------------------------------------------------------
    Exts skipped    :    0
    Exts tested     :   45
    ---------------------------------------------------------------------
    
    Number of tests :   52                52
    Tests skipped   :    0 (  0.0%) --------
    Tests warned    :    0 (  0.0%) (  0.0%)
    Tests failed    :   17 ( 32.7%) ( 32.7%)
    Expected fail   :    0 (  0.0%) (  0.0%)
    Tests passed    :   35 ( 67.3%) ( 67.3%)
    ---------------------------------------------------------------------
    Time taken      :    7 seconds
    =====================================================================
    
    =====================================================================
    FAILED TEST SUMMARY
    ---------------------------------------------------------------------
    memcache_delete() [tests/008.phpt]
    memcache->delete() [tests/016.phpt]
    memcache->addServer() [tests/019.phpt]
    memcache->set()/memcache->get() with multiple keys and load balancing [tests/020.phpt]
    memcache->getExtendedStats() [tests/022.phpt]
    memcache_get_extended_stats() [tests/022a.phpt]
    memcache->delete() with load balancing [tests/023.phpt]
    memcache->increment() with load balancing [tests/025.phpt]
    memcache->delete() with load balancing [tests/026.phpt]
    ini_set("memcache.chunk_size") [tests/030.phpt]
    memcache->addServer() adding server in failed mode [tests/031.phpt]
    memcache->getServerStatus(), memcache->setServerParams() [tests/032.phpt]
    memcache->getStats() with arguments [tests/034.phpt]
    memcache::connect() with unix domain socket [tests/035.phpt]
    ini_set('session.save_handler') [tests/036.phpt]
    hash strategies and functions [tests/046.phpt]
    ini_set('session.save_handler') with unix domain socket [tests/053.phpt]
    =====================================================================