Brendan Tildesley <brendan.tildesley@openmailbox.org> writes:

> * gnu/packages/ebook.scm (calibre)[arguments]: Install mimetypes xml file.
> ---
>  gnu/packages/ebook.scm | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/gnu/packages/ebook.scm b/gnu/packages/ebook.scm
> index 659ec57d5..5c392cc75 100644
> --- a/gnu/packages/ebook.scm
> +++ b/gnu/packages/ebook.scm
> @@ -183,7 +183,12 @@
>                         (find-files (string-append
>                                      (assoc-ref inputs "font-liberation")
>                                      "/share/fonts/truetype")))
> -             #t)))))
> +             #t))
> +         (add-after 'install-font-liberation 'install-mimetypes
> +           (lambda* (#:key outputs #:allow-other-keys)
> +             (install-file "resources/calibre-mimetypes.xml"
> +                           (string-append (assoc-ref outputs "out")
> +                                          "/share/mime/packages")))))))

(install-file ...) has an unspecified return value, so I added a #t here.