ports/editors/nvi-m17n has a checksum error for file nvi-m17n.tar.gz.
  The archive file has modified on a master ftp site ftp://sleepy.vwh.net/pub/.
Another master site ftp://ftp.foretune.co.jp/pub/tools/nvi-m17n/ has old one.

  The differences of two archives are "LICENSE" and "README" only, so
"make NO_CHECKSUM=yes" works fine.

Fix: 

a) "make NO_CHECKSUM=yes" works fine.
b) Remove ftp.foretune.co.jp from MASTER_SITES and update checksum in distfile. 
   ports/distfiles/nvi-nvi-1.79.tar.gz on FreeBSD ftp sites should be updated.
c) Remove sleeply.vwh.net from MASTER_SITES. (I'm not sure is's good or not.)
How-To-Repeat: 
  Following commands failed by checksum mismatch for nvi-1.79.tar.gz:

# cd /usr/ports/editors/nvi-m17n
# make distclean
# make

  I checked the differences between old and new archive by following commands:

% fetch -q -o sleepy.tar.gz ftp://sleepy.vwh.net/pub/nvi-1.79.tar.gz
% mkdir sleepy; tar xzfC sleepy.tar.gz sleepy
% fetch -q -o foretune.tar.gz ftp://ftp.foretune.co.jp/pub/tools/nvi-m17n/nvi-1.79.tar.gz
% mkdir foretune; tar xzfC foretune.tar.gz foretune
% md5 sleepy.tar.gz foretune.tar.gz
MD5 (sleepy.tar.gz) = 765e2153f5fc4f21793f2edc2647305a
MD5 (foretune.tar.gz) = 52549f8e390db06f9366ee83e59f64de
% rsync -a --delete  --dry-run sleepy/ foretune/
building file list ... done
nvi-1.79/LICENSE
nvi-1.79/README
wrote 8172 bytes  read 28 bytes  16400.00 bytes/sec
total size is 4581240  speedup is 558.69
% fgrep nvi-1.79.tar.gz /usr/ports/editors/nvi-m17n/distinfo 
MD5 (nvi-1.79.tar.gz) = 52549f8e390db06f9366ee83e59f64de
%