SFElibiconv only builds 32bit binaries.
64bit should also be build since some software that depends on libiconv fails when building in 64bit because of the missing 64bit libraries.
I put the request into the TODO file.
Thanks for the request, it'll take a little until we can add the support.
To volunteers (SFE is all about that): We already have existing examples for 32-/64-bit, so it should be doable in a short time.
Solved with rev 5967 on 20150618