Support for 64-bit addressing is experimental: some aspects of Perl may
    be omitted or buggy. Note the messages output by Configure for further
    information. Please use "perlbug" to submit a problem report in the
    event that you encounter difficulties.

    When building 64-bit modules, it is your responsiblity to ensure that
    linked external libraries and frameworks provide 64-bit support: if they
    do not, module building may appear to succeed, but attempts to use the
    module will result in run-time dynamic linking errors, and subsequent
    test failures. You can use "file" to discover the architectures
    supported by a library:

        $ file libgdbm.3.0.0.dylib 
        libgdbm.3.0.0.dylib: Mach-O fat file with 2 architectures
        libgdbm.3.0.0.dylib (for architecture ppc):      Mach-O dynamically linked shared library ppc
        libgdbm.3.0.0.dylib (for architecture ppc64):    Mach-O 64-bit dynamically linked shared library ppc64

    Note that this issue precludes the building of many Macintosh-specific
    CPAN modules ("Mac::*"), as the required Apple frameworks do not provide
    PPC64 support. Similarly, downloads from Fink or Darwinports are
    unlikely to provide 64-bit support; the libraries must be rebuilt from
    source with the appropriate compiler and linker flags. For further
    information, see Apple's *64-Bit Transition Guide* at
    <http://developer.apple.com/documentation/Darwin/Conceptual/64bitPorting
    /index.html>.