Updated apr-util to 1.6.0.

Changes with APR-util 1.6.0

  *) Mark apr_dbd_freetds as unsupported, and remove it from all builds
    [Nick Kew]

  *) Update MySQL build to stop using libmysqlclient_r.
    [Petr Sumbera <petr.sumbera oracle.com>]

  *) apr_buckets: Add apr_bucket_file_set_buf_size() which allows to configure
    the size of the buffer used to read files.  [Yann Ylavic]

  *) apr_crypto: avoid excessive iteration in bcrypt hash.
    [Hanno B旦ck <hanno hboeck.de>]

  *) apr_siphash: Implement keyed hash function SipHash.  [Yann Ylavic]

  *) apr_crypto: Add apr_crypto_key() function which supports keys
    generated from a passphrase or a raw secret provided by the caller.
    Deprecate apr_crypto_passphrase(). [Graham Leggett]

  *) apr_crypto_nss: Ensure the SECItem returned by PK11_ParamFromIV
    is properly freed. [Graham Leggett]

  *) apr_crypto: Don't cache the driver if initialisation fails. This
    stops the second and subsequent attempt to use the API from failing
    claiming the library is not initialised. [Graham Leggett]

  *) apr_crypto: Add a native CommonCrypto implementation for iOS and OSX
    where OpenSSL has been deprecated. [Graham Leggett]

  *) apr_xml_to_text: Add style APR_XML_X2T_PARSED to maintain a
    consistent namespace prefix. [Jari Urpalainen
    <jari.urpalainen nokia.com>]

(wiz)