gnu: anki: Fix mpv audio playback

* gnu/packages/patches/anki-mpv-args.patch: New file.
* gnu/local.mk (dist_patch_DATA): Adjust accordingly.
* gnu/packages/education.scm (anki): Adjust accordingly, wrap anki's
  PATH to include mpv executable.

Signed-off-by: Jakub Kądziołka <kuba@kadziolka.net>

gnu/local.mk

@@ -718,6 +718,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/akonadi-timestamps.patch		\
   %D%/packages/patches/allegro-mesa-18.2.5-and-later.patch	\
   %D%/packages/patches/amule-crypto-6.patch			\
+  %D%/packages/patches/anki-mpv-args.patch			\
   %D%/packages/patches/antiword-CVE-2014-8123.patch			\
   %D%/packages/patches/antlr3-3_1-fix-java8-compilation.patch	\
   %D%/packages/patches/antlr3-3_3-fix-java8-compilation.patch	\

gnu/packages/education.scm

@@ -738,7 +738,8 @@ (define-public anki
        (uri (string-append "https://apps.ankiweb.net/downloads/archive/anki-"
                            version "-source.tgz"))
        (sha256
-        (base32 "1gfr51rnllkyzli73p4r51h5ypzfa3m7lic3m3rzpywmqwrxs07k"))))
+        (base32 "1gfr51rnllkyzli73p4r51h5ypzfa3m7lic3m3rzpywmqwrxs07k"))
+       (patches (search-patches "anki-mpv-args.patch"))))
     (build-system gnu-build-system)
     (arguments
      `(#:make-flags (list (string-append "PREFIX=" %output))
@@ -779,6 +780,9 @@ (define-public anki
                            (wrap-program program
                              `("QTWEBENGINEPROCESS_PATH" =
                                (,qtwebengineprocess))
+                             `("PATH" prefix (,(string-append
+                                                (assoc-ref inputs "mpv")
+                                                "/bin")))
                              `("PYTHONPATH" = ,site-packages)))
                          (find-files bin ".")))
              #t)))))

gnu/packages/patches/anki-mpv-args.patch

@@ -0,0 +1,42 @@
+Modified from upstream commit:
+https://github.com/ankitects/anki/commit/ccd715013609133c55e83924734efa78abc03326
+Fixes mpv argument syntax (support for old syntax removed in mpv 0.31):
+https://anki.tenderapp.com/discussions/ankidesktop/38186-mpvprocesserror-unable-to-start-process
+Necessary because we are currently unable to upgrade anki to the
+latest version in guix (NPM dependencies currently unpackaged).
+---
+ anki/mpv.py   | 4 ++--
+ anki/sound.py | 1 -
+ 2 files changed, 2 insertions(+), 3 deletions(-)
+
+diff --git a/anki/mpv.py b/anki/mpv.py
+index f53d9d0..563fddc 100644
+--- a/anki/mpv.py
++++ b/anki/mpv.py
+@@ -104,9 +104,9 @@ class MPVBase:
+         """
+         self.argv = [self.executable]
+         self.argv += self.default_argv
+-        self.argv += ["--input-ipc-server", self._sock_filename]
++        self.argv += ["--input-ipc-server="+self._sock_filename]
+         if self.window_id is not None:
+-            self.argv += ["--wid", str(self.window_id)]
++            self.argv += ["--wid="+str(self.window_id)]
+ 
+     def _start_process(self):
+         """Start the mpv process.
+diff --git a/anki/sound.py b/anki/sound.py
+index aa3431b..a5fce44 100644
+--- a/anki/sound.py
++++ b/anki/sound.py
+@@ -124,7 +124,6 @@ class MpvManager(MPV):
+ def setMpvConfigBase(base):
+     mpvConfPath = os.path.join(base, "mpv.conf")
+     MpvManager.default_argv += [
+-        "--no-config",
+         "--include="+mpvConfPath,
+     ]
+ 
+-- 
+2.25.1
+