Update to 2.4
    
    - New upstream release 2.4:
      - Python 3 support! PyCrypto now supports every version of Python from 2.1
        through to 3.2
      - Timing-attack countermeasures in _fastmath: when built against libgmp
        version 5 or later, we use mpz_powm_sec instead of mpz_powm, which should
        prevent the timing attack described by Geremy Condra at PyCon 2011
      - New hash modules (for Python ≥ 2.5 only): SHA224, SHA384 and SHA512
      - Configuration using GNU autoconf, which should help fix a bunch of build
        issues
      - Support using MPIR as an alternative to GMP
      - Improve the test command in setup.py, by allowing tests to be performed on
        a single sub-package or module only
      - Fix double-decref of "counter" when Cipher object initialization fails
      - Apply patches from Debian's python-crypto 2.3-3 package:
        - fix-RSA-generate-exception.patch
        - epydoc-exclude-introspect.patch
        - no-usr-local.patch
      - Fix launchpad bug #702835: "Import key code is not compatible with GMP
        library"
      - More tests, better documentation, various bugfixes
    - Update patch for imposing our own compiler optimization flags
    - Drop lib64 patch, no longer needed
    - No longer need to fix up permissions and remove shellbangs