diff --git a/contrib/automation/hgautomation/windows.py b/contrib/automation/hgautomation/windows.py
--- a/contrib/automation/hgautomation/windows.py
+++ b/contrib/automation/hgautomation/windows.py
@@ -71,7 +71,7 @@
 BUILD_INNO = r'''
 Set-Location C:\hgdev\src
 $python = "C:\hgdev\python27-{arch}\python.exe"
-C:\hgdev\python37-x64\python.exe contrib\packaging\packaging.py inno --python $python
+C:\hgdev\python37-x64\python.exe contrib\packaging\packaging.py inno --python $python {extra_args}
 if ($LASTEXITCODE -ne 0) {{
     throw "process exited non-0: $LASTEXITCODE"
 }}