Description of problem: libsilc appears to have a statically linked copy of the stringprep implementation from libidn which isn't namespace-protected: jorton@jolt:~$ nm -D /usr/lib/libsilc.so | grep stringprep ... 0000f9b0 T stringprep 0000f2c0 T stringprep_4i 0000fc00 T stringprep_4zi ... this should either be namespace-protected properly, or (ideally) libsilc should just link against libidn for stringprep support.
Complete list of global symbol conflicts from this library: Clashes for /usr/lib/libsilc-1.0.so.2.4.1: with /usr/lib/libidn.so.11.5.19 => stringprep_rfc3454_B_2 stringprep_rfc3454_B_3 (...23 symbols omitted...) stringprep_rfc3454_A_1 with /usr/lib/libpisock.so.8.0.5 => MD5Transform MD5Init MD5Update MD5Final with /usr/lib/libgs.so.8.15 => mem_close mem_open with /usr/lib/libncp.so.2.3.0 => mp_div mp_mod mp_neg mp_init
libsilc in rawhide now links against libidn for stringprep support, and I believe the other conflicts have been resolved upstream some time ago so this should all be fixed in rawhide now.