doc: document libyang cache bug workaround

Document workaround for
https://github.com/CESNET/libyang/issues/752

Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>

diff --git a/doc/developer/building-libyang.rst b/doc/developer/building-libyang.rst
index 41fe09e322fef4445a432106dc750c8de0ac3877..ea5f84d2ba7d9a5f3d6e5fc37606a2966db06ac5 100644 (file)
--- a/doc/developer/building-libyang.rst
+++ b/doc/developer/building-libyang.rst
@@ -50,6 +50,7 @@ The FRR project builds binary ``libyang`` packages, which we offer for download
    make
    sudo make install
 
-When building libyang on CentOS 6, it's also necessary to pass the
-``-DENABLE_CACHE=OFF`` parameter to cmake.
+When building ``libyang`` version ``0.16.x`` it's also necessary to pass the
+``-DENABLE_CACHE=OFF`` parameter to ``cmake`` to work around a
+`known bug <https://github.com/CESNET/libyang/issues/752>`_ in libyang.