Here's a patch to restore the old usage of __int__ to convert non-integer arguments;  it also produces a DeprecationWarning whenever __int__ is used in this way.  For consistency and simplicity, __int__ will be tried for *any* non-integer argument when packing with an integer format;  this goes beyond the conversions that 2.6 allows. (In 2.6, the behaviour is somewhat random: it works only for 'bBhHil' in native mode and 'bhil' in non-native mode.)

It doesn't seem worth deliberately trying __long__ as well, so I've left that out.  So there's still some possibility for breakage relative to 2.6, when (1) packing using 'Q' or 'q', *and* (2) the object to be packed defines __long__ but not __int__, or defines both __long__ and __int__ in inconsistent ways.  The likelihood of (2) seems small enough that this isn't worth worrying about in practice (and the workaround is easy, too).

Andreas, are you in a position to test this patch?

Supporting conversions to integer via __index__ is orthogonal to this;  I'll take a look at Meador's patch shortly.