Thanks for the patch!  Just a few nitpicks below:

On Thu, 31 Jan 2019 15:43:26 +0900
Yoshinori Arai <kumagusu08@gmail.com> wrote:

> 1 file changed, 38 insertions(+)
> gnu/packages/textutils.scm | 38 ++++++++++++++++++++++++++++++++++++++
> 
> modified   gnu/packages/textutils.scm
> @@ -794,3 +794,41 @@ Chinese and Simplified Chinese, supporting character-level conversion,
>  phrase-level conversion, variant conversion, and regional idioms among
>  Mainland China, Taiwan, and Hong-Kong.")
>      (license license:asl2.0)))
> +
> +(define-public nkf
> +  (let ((commit "08043eadf4abdddcf277842217e3c77a24740dc2")

Could you add a comment about how this commit relates to the 2.1.5
release?  I see the github page doesn't seem to make actual releases,
or even tag.  Would it make any sense to download the tarballs
available at https://ja.asdn.net/projects/nkf instead?

> +        (revision "1"))
> +    (package
> +      (name "nkf")
> +      (version "2.1.5")
> +      (source (origin
> +                (method git-fetch)
> +                (uri (git-reference
> +                      (url "https://github.com/nurse/nkf.git")
> +                      (commit commit)))
> +                (file-name (string-append name version))

Rather than string-append use the 'git-file-name' procedure.

> +                (sha256
> +                 (base32
> +                  "0anw0knr1iy4p9w3d3b3pbwzh1c43p1i2q4c28kw9zviw8kx2rly"))))
> +      (build-system gnu-build-system)
> +      (arguments
> +       `(#:tests? #f ; test for perl module
> +         #:make-flags (list "CC=gcc" "CFLAGS=-O2 -Wall -pedantic"
> +                            (string-append "prefix=" %output))
> +         #:phases
> +         (modify-phases %standard-phases
> +           (delete 'configure)
> +           (replace 'install

The Makefile's 'install' target seems like it might do what we want.
Is that not the case?

> +             (lambda* (#:key outputs #:allow-other-keys)
> +               (let* ((out (assoc-ref outputs "out"))
> +                      (bin (string-append out "/bin"))
> +                      (man1 (string-append out "/share/man/man1"))
> +                      (man1j (string-append out "/share/man/ja/man1")))
> +                 (install-file "nkf" bin)
> +                 (install-file "nkf.1" man1)
> +                 (install-file "nkf.1j" man1j)
> +                 #t))))))
> +      (home-page "https://ja.osdn.net/projects/nkf/")
> +      (synopsis "Network Kanji Filter")
> +      (description "Nkf is a yet another kanji code converter among networks, hosts and terminals. It converts input kanji code to designated kanji code such as ISO-2022-JP, Shift_JIS, EUC-JP, UTF-8, UTF-16 or UTF-32.")
> +      (license license:zlib))))

'is a yet' -> 'is yet'

Use double-space after end-of-sentence period.

Also, make sure to run 'guix lint knf'

Could you send an updated patch?

Thanks,
`~Eric