gnu: Add dragonfly-reverb

* gnu/packages/music.scm (dragonfly-reverb): New variable.

gnu/packages/music.scm

@@ -5213,3 +5213,55 @@ (define-public zrythm
 plugin support, JACK support and chord assistance.")
    (home-page "https://www.zrythm.org")
    (license license:agpl3+)))
+
+(define-public dragonfly-reverb
+  (package
+    (name "dragonfly-reverb")
+    (version "2.0.0")
+    (source
+     (origin
+       (method git-fetch)
+       (uri
+        (git-reference
+         (url "https://github.com/michaelwillis/dragonfly-reverb.git")
+         (commit version)
+         ;; Bundles a specific commit of the DISTRHO plugin framework.
+         (recursive? #t)))
+       (file-name (git-file-name name version))
+       (sha256
+        (base32 "1qrbv4kk5v6ynx424h1i54qj0w8v6vpw81b759jawxvzzprpgq72"))))
+    (build-system gnu-build-system)
+    (arguments
+     `(#:tests? #f                      ; no check target
+       #:make-flags (list "CC=gcc")
+       #:phases
+       (modify-phases %standard-phases
+         (delete 'configure)            ;no configure target
+         (replace 'install              ;no install target
+           (lambda* (#:key outputs #:allow-other-keys)
+             (let* ((out (assoc-ref outputs "out"))
+                    (bin (string-append out "/bin"))
+                    (lv2 (string-append out "/lib/lv2")))
+               ;; Install LV2.
+               (for-each
+                (lambda (file)
+                  (copy-recursively file
+                                    (string-append lv2 "/" (basename file))))
+                (find-files "bin" "\\.lv2$" #:directories? #t))
+               ;; Install executables.
+               (install-file "bin/DragonflyRoomReverb" bin)
+               (install-file "bin/DragonflyHallReverb" bin)
+               #t))))))
+    (native-inputs
+     `(("pkg-config" ,pkg-config)))
+    (inputs
+     `(("jack" ,jack-1)
+       ("libx11" ,libx11)
+       ("mesa" ,mesa)))
+    (home-page "https://michaelwillis.github.io/dragonfly-reverb/")
+    (synopsis "Concert hall reverb and room reverb effects")
+    (description
+     "Dragonfly Reverb is a bundle of two free audio effects: a concert
+hall reverb and a room reverb.  Both are available as LV2 plugins as well
+as JACK standalone applications.")
+    (license license:gpl3+)))