Merge branch 'PHP-5.5'

* PHP-5.5:
  backward compatibility
  HASH_KEY_NON_EXISTANT fix

diff --cc Zend/zend_hash.c
Simple merge

diff --cc Zend/zend_vm_def.h
Simple merge

diff --cc Zend/zend_vm_execute.h
Simple merge

diff --cc ext/standard/var.c
Simple merge