gnu: Add python-mediafile.

* gnu/packages/music.scm (python-mediafile): New variable.
* gnu/packages/patches/python-mediafile-wavpack.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.

gnu/packages/patches/python-mediafile-wavpack.patch

@@ -0,0 +1,57 @@
+This patch has already been applied upstream, but is not included in the
+current release 0.6.0.
+
+From d2fc3b59f77c515b02dfe7ad936f89264375d2b4 Mon Sep 17 00:00:00 2001
+From: Adrian Sampson <adrian@radbox.org>
+Date: Wed, 29 Jul 2020 19:42:57 -0400
+Subject: [PATCH] Fix test for WavPack bitrate
+
+Fixes #34.
+---
+ docs/index.rst         | 5 +++++
+ mediafile.py           | 2 +-
+ test/test_mediafile.py | 2 +-
+ 3 files changed, 7 insertions(+), 2 deletions(-)
+
+diff --git a/docs/index.rst b/docs/index.rst
+index 7b622df..1465405 100644
+--- a/docs/index.rst
++++ b/docs/index.rst
+@@ -100,6 +100,11 @@ Internals
+ Changelog
+ ---------
+ 
++v0.7.0
++''''''
++
++- Mutagen 1.45.0 or later is now required.
++
+ v0.6.0
+ ''''''
+ 
+diff --git a/mediafile.py b/mediafile.py
+index 23fadaf..9e9d063 100644
+--- a/mediafile.py
++++ b/mediafile.py
+@@ -56,7 +56,7 @@
+ import six
+ 
+ 
+-__version__ = '0.6.0'
++__version__ = '0.7.0'
+ __all__ = ['UnreadableFileError', 'FileTypeError', 'MediaFile']
+ 
+ log = logging.getLogger(__name__)
+diff --git a/test/test_mediafile.py b/test/test_mediafile.py
+index e9e1850..7f17f44 100644
+--- a/test/test_mediafile.py
++++ b/test/test_mediafile.py
+@@ -907,7 +907,7 @@ class WavpackTest(ReadWriteTestBase, unittest.TestCase):
+         'bitrate': 109312,
+         'format': u'WavPack',
+         'samplerate': 44100,
+-        'bitdepth': 0,
++        'bitdepth': 16,
+         'channels': 1,
+     }
+