Merge pull request matplotlib#5019 from jheinen/master

Default to UTF-8 if locale.getdefaultlocale() returns None for the encoding

Author: jkseppan

lib/matplotlib/__init__.py

@@ -992,6 +992,8 @@ def _open_file_or_url(fname):
     else:
         fname = os.path.expanduser(fname)
         encoding = locale.getdefaultlocale()[1]
+        if encoding is None:
+            encoding = "utf-8"
         with io.open(fname, encoding=encoding) as f:
             yield f