run commands with shell=True

appears to be needed on Windows,
and should be harmless elsewhere.

setupbase.py

@@ -297,6 +297,7 @@ def mtime(path):
 def run(cmd, *args, **kwargs):
     """Echo a command before running it"""
     log.info(" ".join(cmd))
+    kwargs.setdefault('shell', True)
     return check_call(cmd, *args, **kwargs)