Yocto 2.2 uses rrdtool 1.6.0 which is now threadsafe by default, so -lrrd_th is now deprecated, this library no longer exists.
I'll update our pre 2.2 OE with rrdtool 1.6.0 so that we do not run into build problems once this change is merged.
implements #15132
I checked this on Fedora 24, I would ask those using Ubuntu and Debian to try it out as well: @chhitz, @taw