Raised on FreeBSD 12.2, seen not corrected in FreeBSD 13 as well. Q/A tests complain USES+=iconv is missing in Makefile.
Looking for something else (not being maintainer of this port) I found this report and believe it has been addressed back in 2021 with: commit a0e752df801309c38f6ccd64a25ae064db870ed9 Author: Yasuhiro Kimura <yasu@utahime.org> Date: Thu Aug 5 09:14:21 2021 +0200 devel/binutils: Update to 2.37 Unfortunately, like too many commits, it did not properly mention (in the commit log) nor document (in the code) such a change, it did bring the following, however: +.if ${FLAVOR} == mingw32 +USES+= iconv +.endif I am sorry you did not get an earlier response, though at least the issue was resolved within two months.