(define (ocaml-forge-uri name version file-number)

  (string-append "https://forge.ocamlcore.org/frs/download.php/"

                 (number->string file-number) "/" name "-" version

                 ".tar.gz"))

    (version "4.06.0")

                "1dy542yfnnw10zvh5s9qzswliq11mg7l0bcyss3501qw3vwvadhj"))))

    (version "4.06+1")

			    "08mrp8jjaayv0s50kmhjkafxqykff5dq3073hrl7ylx0km253k5i"))))

    (version "1.7.3")

    (source (origin

              (method url-fetch)

              (uri (string-append "http://download.camlcity.org/download/findlib-"

                                  version ".tar.gz"))

              (sha256

               (base32

                "12xx8si1qv3xz90qsrpazjjk4lc1989fzm97rsmc4diwla7n15ni"))))

    (arguments

      (substitute-keyword-arguments (package-arguments ocaml-findlib)

        ((#:phases phases)

          `(modify-phases ,phases

            (add-before 'build 'fix-findlib-makefile

              (lambda* (#:key outputs #:allow-other-keys)

                (substitute* "Makefile.config"

                  (("OCAML_CORE_STDLIB=.*")

                   (string-append "OCAML_CORE_STDLIB="

                                  (assoc-ref outputs "out") "/lib/ocaml/site-lib"

                                  "\n")))

                #t))))))

    (version "2.18.6")

    (source (origin

              (method url-fetch)

              (uri (ocaml-forge-uri "lablgtk" version 1726))

              (sha256

               (base32

                "1y38fdvswy6hmppm65qvgdk4pb3ghhnvz7n4ialf46340r1s5p2d"))))

    (arguments

     `(#:tests? #f ; no check target

       ;; opt: also install cmxa files

       #:make-flags (list "all" "opt"

                          "OCAMLFIND=ocamlfind"

                          "OCAMLLDCONF=ld.conf"

                          (string-append "FINDLIBDIR="

                                         (assoc-ref %outputs "out")

                                         "/lib/ocaml"))

       ;; Occasionally we would get "Error: Unbound module GtkThread" when

       ;; compiling 'gtkThInit.ml', with 'make -j'.  So build sequentially.

       #:parallel-build? #f

       #:phases

         (modify-phases %standard-phases

           (add-before 'install 'prepare-install

             (lambda* (#:key inputs outputs #:allow-other-keys)

               (let ((out (assoc-ref outputs "out"))

                     (ocaml (assoc-ref inputs "ocaml")))

                 ;; Install into the output and not the ocaml directory.

                 (mkdir-p (string-append out "/lib/ocaml"))

                 (substitute* "config.make"

                   ((ocaml) out))

                 #t))))))

    (home-page "http://lablgtk.forge.ocamlcore.org/")