libidn.so.11 is contained in the libidn-0.5.8 (atleast thats the version in current).
According to pkgtool, it does not contain libidn.so.11, but it does contain
libidn.so.11.5.1 . ( /usr/lib/libidn.so.11.5.1 )
Not sure, but you may try creating a symlink from libidn.so.11 to the existing libidn.so.11.5.1?
Once or twice I've had to do similar things in the past. Maybe its not the best idea, or
the proper way, but I do remember it working for me. If theres a better way, I'de like to
hear it myself incase I run into a similar situation again.