When using a Python that has not been installed to
build 3rd-party modules, distutils does not understand
that the build version of the source tree is needed.

This patch fixes distutils.sysconfig to understand that
the running Python is part of the build tree and needs
to use the appropriate "shape" of the tree.  This does
not assume anything about the current directory, so can
be used to build 3rd-party modules using Python's build
tree as well.

This is useful since it allows us to use a
non-installed debug-mode Python with 3rd-party modules
for testing.  It as the side-effect that
set_python_build() is no longer needed (the hack which
was added to allow distutils to be used to build the
"standard" extension modules).

Logged In: YES 
user_id=6656

Fred, can you look at

[ 458898 ] --python-build for install

(which has been sitting on my plate for an embarrassingly
long time)

Is it solving the same problem?  Which appraoch do you prefer?

Logged In: YES 
user_id=3066

Based on the descriptions, this solves a closely related
problem to what's addressed by patch 458898.  I've not read
that patch, but it sounds like there are likely conflicts
between the two patches due to needing to touch related
code, but the approaches are different.  I'd have to spend
more time looking at that patch to see what's going on, but
it's not clear that the approach (or the problem statement)
makes sense.

These issues should be discussed in the distutils SIG.

Logged In: YES 
user_id=3066

Guido found this useful, so it's now checked in as setup.py
revision 1.88 and Lib/distutils/sysconfig.py revision 1.46.

Bugfix candidate.