Suppress compilation of py3_ files upon installation.
diff --git a/Tools/msi/msi.py b/Tools/msi/msi.py
index c12e43b..596a2cb 100644
--- a/Tools/msi/msi.py
+++ b/Tools/msi/msi.py
@@ -375,7 +375,7 @@
               ("VerdanaRed9", "Verdana", 9, 255, 0),
              ])
 
-    compileargs = r'-Wi "[TARGETDIR]Lib\compileall.py" -f -x bad_coding|badsyntax|site-packages "[TARGETDIR]Lib"'
+    compileargs = r'-Wi "[TARGETDIR]Lib\compileall.py" -f -x bad_coding|badsyntax|site-packages|py3_ "[TARGETDIR]Lib"'
     # See "CustomAction Table"
     add_data(db, "CustomAction", [
         # msidbCustomActionTypeFirstSequence + msidbCustomActionTypeTextData + msidbCustomActionTypeProperty