bpo-34421 avoid unicode error in distutils logging (GH-8799)

This caused installation errors in some cases on Windows.
Patch by Julien Malard.

Lib/distutils/log.py

@@ -31,7 +31,10 @@ class Log:
                 # emulate backslashreplace error handler
                 encoding = stream.encoding
                 msg = msg.encode(encoding, "backslashreplace").decode(encoding)
-            stream.write('%s\n' % msg)
+            try:
+                stream.write('%s\n' % msg)
+            except UnicodeEncodeError:
+                stream.write('%s\n' % msg.encode('unicode-escape').decode('ascii'))
             stream.flush()
 
     def log(self, level, msg, *args):

Misc/NEWS.d/next/Library/2018-09-07-10-57-00.bpo-34421.AKJISD.rst

@@ -0,0 +1 @@
+Fix distutils logging for non-ASCII strings.  This caused installation issues on Windows.