Don't load intersphinx extension when building PHCpy docs. It isn't used and also attempted to access the network, which may not be available (e.g., when building Debian packages.)
Also add directory containing phcpy to sys.path for sphinx. Otherwise, autodoc won't be able to import the polynomials module as it tries to import phcpy.
Two things:
phcpy
tosys.path
for sphinx. Otherwise, autodoc won't be able to import thepolynomials
module as it tries to importphcpy
.