USE_LIBXC=-1 to use libxc pkgs

.github/workflows/github_actions.yml

@@ -136,6 +136,7 @@ jobs:
             nwchem_modules: "qmandpw qmd"
             fc: gfortran-11
             cc: gcc-11
+            use_libxc: -1
           - os: ubuntu-20.04
             experimental: true
             mpi_impl: mpich

travis/build_env.sh

@@ -145,6 +145,9 @@ fi
         sudo  apt-get -y install gcc-11 gfortran-11 g++-11
     fi
     fi
+    if [[ "$USE_LIBXC" == "-1" ]]; then
+	sudo apt-get -y install libxc-dev
+    fi
     if [[ "$FC" == "ifort" ]] || [[ "$FC" == "ifx" ]]; then
         sh ./"$base".sh -a -c -s --action remove --install-dir $IONEAPI_ROOT   --eula accept
         sh ./"$hpc".sh -a -c -s --action remove --install-dir  $IONEAPI_ROOT  --eula accept

travis/nwchem.bashrc

@@ -188,3 +188,9 @@ if [[ "$FC" == "gfortran" ]]; then
      export NWCHEM_MODULES=$(echo $NWCHEM_MODULES |sed  's/xtb//')
    fi
 fi
+
+if [[ "$USE_LIBXC" == "-1" ]]; then
+    unset USE_LIBXC
+    export LIBXC_LIB=/usr/lib/x86_64-linux-gnu
+    export LIBXC_INCLUDE=/usr/include
+fi