Issue #13193: Fix distutils.filelist.FileList under Windows.  The
"recursive-include" directive now recognizes both legal path separators.
diff --git a/Lib/distutils/filelist.py b/Lib/distutils/filelist.py
index 4aac6d3..ebd1411 100644
--- a/Lib/distutils/filelist.py
+++ b/Lib/distutils/filelist.py
@@ -328,7 +328,10 @@
         # ditch end of pattern character
         empty_pattern = glob_to_re('')
         prefix_re = glob_to_re(prefix)[:-len(empty_pattern)]
-        pattern_re = "^" + os.path.join(prefix_re, ".*" + pattern_re)
+        # match both path separators, as in Postel's principle
+        sep_pat = "[" + re.escape(os.path.sep + os.path.altsep
+                                  if os.path.altsep else os.path.sep) + "]"
+        pattern_re = "^" + sep_pat.join([prefix_re, ".*" + pattern_re])
     else:                               # no prefix -- respect anchor flag
         if anchor:
             pattern_re = "^" + pattern_re
diff --git a/Misc/NEWS b/Misc/NEWS
index 9517677..259d08a 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -76,6 +76,9 @@
 Library
 -------
 
+- Issue #13193: Fix distutils.filelist.FileList under Windows.  The
+  "recursive-include" directive now recognizes both legal path separators.
+
 - Issue #13373: multiprocessing.Queue.get() could sometimes block indefinitely
   when called with a timeout.  Patch by Arnaud Ysmal.