homepage

PYTHONHOME is defined as 'prefix:exec-prefix'. Given that definition
the library must be resolved relatively by appending 'lib/pythonX.Y'. 
Given the long standing nature of this interface, I doubt the meaning
can be changed.
It might be possible to _extend_ the definition of PYTHONHOME to have
additional elements, one of which would be libdir. It seems to me that
this would be backward compatible. This possibility, and/or other
solutions, would be more appropriately discussed on python-ideas. And
then of course someone would have to develop a patch to implement
whatever scheme wins consensus (assuming the consensus is that this is a
problem worth solving).