If binary is copied, prefix-finding could be broken
If we use a copied rather than symlinked binary, the finding of sys.prefix (in getpath.c) relies on falling back on the ./configure prefix. This might be broken in some situations, if the installation of Python that the virtualenv was created from has an incorrect ./configure prefix for some reason and was relying instead on the path-climbing behavior to find its sys.prefix, or if path-climbing from the location of the copied binary results in finding a valid (but incorrect) prefix.
Not sure yet how this can be fixed. It will probably require tweaks to getpath.c.