Port Martin von Loewis checkin from python:  Support sdist.
diff --git a/Lib/idlelib/MANIFEST.in b/Lib/idlelib/MANIFEST.in
new file mode 100644
index 0000000..96098f8
--- /dev/null
+++ b/Lib/idlelib/MANIFEST.in
@@ -0,0 +1,4 @@
+include *.txt
+include idle
+include MANIFEST.in
+include MANIFEST