cpp-hocon: fix build w/glibc-2.34

Simply disable tests as it tries to pull in an old `catch2` from
`leatherman`.

Failing Hydra build: https://hydra.nixos.org/build/163982252

pkgs/development/libraries/cpp-hocon/default.nix

···
     owner = "puppetlabs";
   };
 
+  postPatch = ''
+    sed -i -e '/add_subdirectory(tests)/d' lib/CMakeLists.txt
+  '';
+
   NIX_CFLAGS_COMPILE = "-Wno-error";
 
   nativeBuildInputs = [ cmake ];