To download, configure, build, and install LIBXC 2.x, 3.x, or 4.x (CP2K requires LIBXC 4.x and version 5.x is currently not supported), one may proceed as shown below. Please note that CP2K 5.1 (and earlier) is only compatible with LIBXC 3.0 (or earlier, see also How to compile the CP2K code). Post-5.1, only the latest major release of LIBXC (by the time of the CP2K-release) is supported (e.g., LIBXC 4.x).

wget --content-disposition
tar xvf libxc-4.3.4.tar.gz
cd libxc-4.3.4
wget --no-check-certificate
chmod +x
./ libxc

Please make the Intel Compiler available on the command line. This depends on the environment. For instance, many HPC centers rely on module load.

source /opt/intel/compilers_and_libraries_2018.5.274/linux/bin/ intel64

For example, to configure and make for an Intel Xeon Scalable processor ("SKX"):

make distclean
make -j; make install

NOTE: Please disregard messages during configuration suggesting libtoolize --force.