The issue was introduced while moving universal-binary specific trickery
from pyconfig.h.in to a separate header file. Obviously I must have been
drunk at the time, because I didn't move the WORDS_BIGENDIAN bits
correctly.
The attached patch in "pymacconfig.h.patch" adds detection of
WORDS_BIGENDIAN to pymacconfig.h, the header where the other pyconfig.h
overrides for universal builds are as well.
Background: this work was done while adding support for 4-way universal
builds, that is x86, x86_64, ppc and ppc64. This required many more
updates to pyconfig.h, most of which couldn't be done in a clean
platform-independent way. That's why I (tried to) move the setting of
pyconfig.h values that are affected by the current architecture to
Include/pymacconfig.h.
NOTE: I haven't tested my patch yet, I'll do a full test round later
today.