Lion 10.7.3 / Xcode 4.3.2
Using this ./configure:

./configure --without-libiconv-prefix --with-libiconv-prefix=/usr --disable-nls
--enable-symcryptrun --enable-gpgtar

The build of gpgtar will fail with unresolved "iconv" link errors. Neither of
the 1st two ./configure options (either alone or absent altogether) helps.

My workaround was to manually edit the final linking command in ./tools/ to
append "-L/usr -liconv", cd to ./tools/, and run the edited command manually.

Then I switched back to . and continued with the make. Bingo. All "make check"
tests passed.