[racket-dev] Build failure on OS X

I tried to build the git HEAD today and ran into problems. During the make process, it fails to create the framework with the following error message:

gcc -o Racket.framework/Versions/5.1.1.3/Racket  -m32 -pthread -framework CoreFoundation -dynamiclib -all_load  libracket.a libmzgc.a -ldl -lm  -liconv -L/opt/local/lib -lffi   
Undefined symbols:
  "_iconv_close", referenced from:
      _do_convert in libracket.a(string.o)
      _do_convert in libracket.a(string.o)
      _do_convert in libracket.a(string.o)
      _string_to_from_locale in libracket.a(string.o)
      _string_to_from_locale in libracket.a(string.o)
      _string_to_from_locale in libracket.a(string.o)
      _close_converter in libracket.a(string.o)
  "_iconv_open", referenced from:
      _do_convert in libracket.a(string.o)
      _string_to_from_locale in libracket.a(string.o)
      _string_to_from_locale in libracket.a(string.o)
      _scheme_open_converter in libracket.a(string.o)
  "_iconv", referenced from:
      _do_convert in libracket.a(string.o)
ld: symbol(s) not found
collect2: ld returned 1 exit status

Does anyone know what might cause this?

Thanks,
 Eric