Update php71 to 7.1.0rc1 (PHP 7.1.0RC1).

01 Sep 2016, PHP 7.1.0RC1

- Core:
  . Fixed bug #72944 (Null pointer deref in zval_delref_p). (Dmitry)
  . Fixed bug #72943 (assign_dim on string doesn't reset hval). (Laruence)
  . Fixed bug #72598 (Reference is lost after array_slice()) (Nikita)
  . Fixed bug #72703 (Out of bounds global memory read in BF_crypt triggered by
    password_verify). (Anatol)
  . Implement \ArgumentCountError when passing in too few arguments (Davey)

- COM:
  . Fixed bug #72922 (COM called from PHP does not return out parameters).
    (Anatol)

- Dba:
  . Fixed bug #70825 (Cannot fetch multiple values with group in ini file).
    (cmb)

- GD:
  . Fixed bug #66005 (imagecopy does not support 1bit transparency on truecolor
    images). (cmb)
  . Fixed bug #72913 (imagecopy() loses single-color transparency on palette
    images). (cmb)
  . Fixed bug #68716 (possible resource leaks in _php_image_convert()). (cmb)

- iconv:
  . Fixed bug #72320 (iconv_substr returns false for empty strings). (cmb)

- Intl:
  . Fixed bug #65732 (grapheme_*() is not Unicode compliant on CR LF
    sequence). (cmb)

- JSON:
  . Implemented earlier return when json_encode fails, fixes bugs #68992
    (Stacking exceptions thrown by JsonSerializable) and #70275 (On recursion
    error, json_encode can eat up all system memory). (Jakub Zelenka)

- mbstring:
  . Fixed bug #66797 (mb_substr only takes 32-bit signed integer). (cmb)

- Opcache:
  . Fixed bug #72949 (Typo in opcache error message). (cmb)

- PDO_DBlib:
  . Implemented stringify 'uniqueidentifier' fields.
    (Alexander Zhuravlev, Adam Baratz)

- Reflection:
  . Reverted prepending \ for class names. (Trowski)

- Session:
  . Fixed bug #72940 (SID always return "name=ID", even if session
    cookie exist). (Yasuo)
  . Implemented session_gc() and session_create_id() functions. (Yasuo)

- SimpleXML:
  . Fixed bug #72971 (SimpleXML isset/unset do not respect namespace). (Nikita)
  . Fixed bug #72957 (Null coalescing operator doesn't behave as expected with
    SimpleXMLElement). (Nikita)

- SOAP:
  . Fixed bug #71711 (Soap Server Member variables reference bug). (Nikita)
  . Fixed bug #71996 (Using references in arrays doesn't work like expected).
    (Nikita)

- Standard:
  . Fixed bug #72920 (Accessing a private constant using constant() creates
    an exception AND warning). (Laruence)
  . Fixed bug #65550 (get_browser() incorrectly parses entries with "+" sign).
    (cmb)
  . Fixed bug #71882 (Negative ftruncate() on php://memory exhausts memory).
    (cmb)

- XML:
  . Fixed bug #72714 (_xml_startElementHandler() segmentation fault). (cmb)

(taca)