NWPW and DFT-D3
---------------

The NWPW (XC) component of NWChem is expected to be built with support
for DFT-D3 provided by the Grimme group at
https://www.chemie.uni-bonn.de/grimme/de/software/dft-d3

In order to avoid source licence confusion (NWChem is ESL-2, while 
dftd3 is GPL), the NWChem build system normally downloads the latest
version of the dftd3 tarball at build time. But by Debian policy
internet access is not permitted when building Debian packages.

It is possible to set NO_NWPWXC_VDW3A to build without DFT-D3 support,
but it is better to includ it.

For this reason we maintain a local copy of dftd3 at
  debian/dftd3/dftd3.tgz
downloaded (GPL licence) from
  https://www.chemie.uni-bonn.de/grimme/de/software/dft-d3/get_dft-d3
