Running cmake && make DESTDIR=/some/root with make as the generator puts
the build-tree shared object puts the _skbuild dir at DESTDIR, as the
scikit-build make install invocation respects DESTDIR. DESTDIR and
python is already handled by our cmake scripts, so simply hide the fact
that it is in use by deleting it from the env when calling python.
Running cmake && make DESTDIR=/some/root with make as the generator puts the build-tree shared object puts the _skbuild dir at DESTDIR, as the scikit-build make install invocation respects DESTDIR. DESTDIR and python is already handled by our cmake scripts, so simply hide the fact that it is in use by deleting it from the env when calling python.