Q: error while loading shared libraries
A: libyang is installed into the directory detected by CMake's GNUInstallDirs function. However, when it is connected with the installation prefix, the target directory is not necessary the path used by the system linker. Check the linker's paths in /etc/ld.so.conf.d/. If the path where libyang is installed is already present, just make ldconfig to rebuild its cache:
# ldconfig
If the path is not present, you can change the libyang installation prefix when running cmake:
$ cmake -DCMAKE_INSTALL_PREFIX:PATH=/usr ..
or add the libyang's location to the linker paths in /etc/ld.so.conf.d and then run ldconfig to rebuild the linker cache.