> I actually packaged scintilla

Nice!

> but I failed unbundling it from Geany.  I attach the three patches I
> put up so far.

The scintilla package is not producing a shared library
(libscintilla.so). That is why you were not able to link it to geany. It
took a bit of substitute* surgery of the makefiles, but I managed to get
this working. Please see my attached patches. Ideally, we should get
scintilla and geany upstreams to support unbundling. Could you raise
these issues upstream?

> Subject: [PATCH 1/3] gnu: Add scintilla license.
>
> * guix/licenses.scm (scintilla): New variable.

The scintilla license is the ISC license. See
https://directory.fsf.org/wiki/License:ISC

> +         (replace 'build
> +           (lambda _ (invoke "make" "GTK3=1" "CC=gcc" "-Cgtk")))

This can be done by specifying #:make-flags. No need to replace the
build phase.

> +         (replace 'install
> +           (lambda* (#:key outputs #:allow-other-keys)
> +             (let* ((out (assoc-ref outputs "out"))
> +                    (lib (string-append out "/lib/scintilla"))
> +                    (include (string-append out "/include/scintilla")))
> +               (install-file "bin/scintilla.a" lib)
> +               (for-each (lambda (f) (install-file f include))
> +                         (find-files "include/" "."))
> +               #t))))))

The headers should be installed in /include, not in
/include/scintilla. The libraries should be installed in /lib, not in
/lib/scintilla.

The changes specified in the comments above are also included in the
attached patches. Please feel free to refine my patches as required.

Thanks!