Updating devel/p5-Variable-Magic from 0.38 to 0.40

Upstream changes
:0.40    2010-01-06 23:20 UTC
        + Fix : Possible memory miswrites when passing data arguments to cast().
        + Fix : Minor C portability tweaks.

0.39    2009-12-01 00:05 UTC
        + Add : You can use a function name as a callback by passing a string
                reference to wizard() instead of a code reference.
        + Fix : Compatiblity with perl 5.11.1 and 5.11.2.
        + Fix : Scalars stored into the data slot no longer leak.
        + Fix : Thread destruction should not segfault anymore.
        + Opt : As a result of removing the deprecated features, less memory is
                used for both threaded (a pointer table is used instead of a
                hash) and non-threaded (no global structure is needed anymore)
                perls.
        + Rem : As advertised in the precendent version, all the signature
                related features were removed. This includes the 'sig' option
                to wizard(), the getsig() and gensig() functions, and the SIG_*
                constants.

(sno)