$ cd src
$ tar xvzf nkf-2.1.5.tar.gz
$ cd nkf-2.1.5
$ make
$ make install

$ make
cc -g -O2 -Wall -pedantic -c nkf.c
関数 ‘get_backup_filename’ 内,
    inlined from ‘main’ at nkf.c:7164:28:
nkf.c:1035:3: 警告: ‘strncat’ output truncated before terminating nul copying as many bytes from a string as its length [-Wstringop-truncation]
 1035 |   strncat(backup_filename, filename, filename_length);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
nkf.c: 関数 ‘main’ 内:
nkf.c:1024:27: 備考: length computed here
 1024 |     int filename_length = strlen(filename);
      |                           ^~~~~~~~~~~~~~~~
cc -g -O2 -Wall -pedantic -c utf8tbl.c
cc -g -O2 -Wall -pedantic  -o nkf nkf.o utf8tbl.o

$ make install
mkdir /usr/local/bin
mkdir: ディレクトリ `/usr/local/bin' を作成できません: File exists
make: [Makefile:49: install-main] エラー 1 (無視されました)
cp -f nkf /usr/local/bin/
mkdir /usr/local/man
mkdir /usr/local/man/man1
cp -f nkf.1 /usr/local/man/man1/
mkdir /usr/local/man/ja
mkdir /usr/local/man/ja/man1
cp -f nkf.1j /usr/local/man/ja/man1/nkf.1