Here is the result from running jhbuild build libiconv
Shawns-iMac:~ shawn$ jhbuild build libiconv
*** Checking out libiconv *** [1/1]
curl --continue-at - -L
http://ftp.gnu.org/gnu/libiconv/libiconv-1.13.1.tar.gz -o /Users/shawn/gtk/source/pkgs/libiconv-1.13.1.tar.gz
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
1 4605k 1 57684 0 0 54710 0 0:01:26 0:00:01 0:01:25 76301
.....
The important thing to note is the version should be 1.13. I would definitely recommend doing the 32-bit. I believe this is also needed for the 32-bit.