Thanks for reporting this bug
A patch is available
To apply the patch, please do the following
cd $NWCHEM_TOP
curl http://nwchemgit.github.io/images/Xatom_vdw.patch.gz -o Xatom_vdw.patch.gz
gzip -d Xatom_vdw.patch.gz
patch -p0 < Xatom_vdw.patch
cd src/nwdft/xc
make
cd ../..
make link