Updated to LIBXC-5.1.6.

config/libxc/README.md

@@ -3,9 +3,9 @@
 To [download](https://gitlab.com/libxc/libxc/-/releases), configure, build, and install [LIBXC](https://www.tddft.org/programs/libxc/) 2.x, 3.x (CP2K 5.1 and earlier is only compatible with LIBXC 3.0 or earlier), 4.x (CP2K 7.1 and earlier is only compatible with LIBXC 4.x), or 5.x (CP2K 8.1 and later require LIBXC 5.x), one may proceed as shown below. For CP2K, see also [How to compile the CP2K code](https://github.com/cp2k/cp2k/blob/master/INSTALL.md#2k-libxc-optional-wider-choice-of-xc-functionals)). In general, only the latest major release of LIBXC (by the time of the CP2K-release) is supported.
 
 ```bash
-wget --content-disposition https://www.tddft.org/programs/libxc/down.php?file=5.1.5/libxc-5.1.5.tar.gz
-tar xvf libxc-5.1.5.tar.gz
-cd libxc-5.1.5
+wget --content-disposition https://www.tddft.org/programs/libxc/down.php?file=5.1.6/libxc-5.1.6.tar.gz
+tar xvf libxc-5.1.6.tar.gz
+cd libxc-5.1.6
 
 wget --no-check-certificate https://github.com/hfp/xconfigure/raw/master/configure-get.sh
 chmod +x configure-get.sh