#include "nsISupports.idl"

[scriptable, uuid(4ead-ba5c-49c9-beb2=64209c7699a)]
interface nsIPageSummary : nsISupports
{
    boolean saveSummary(in nsIDOMDocument document,
                        out unsigned long numLinks,
                        out unsigned long numImages);
};

$ ~/xulrunner-sdk/sdk/bin/header.py --cachedir=~/xulrunner-sdk/idl -o nsIPageSummary.h nsIPageSummary.idl
Traceback (most recent call last):
  File "~/xulrunner/xulrunner-sdk/sdk/bin/header.py", line 497, in <module>
    idl.resolve(options.incdirs, p)
  File "~/xulrunner/xulrunner-sdk/sdk/bin/xpidl.py", line 285, in resolve
    p.resolve(self)
  File "~/xulrunner-sdk/sdk/bin/xpidl.py", line 255, in resolve
    raise IDLError("File '%s' not found" % self.filename, self.location)
xpidl.IDLError: error: File 'nsISupports.idl' not found, nsIPageSummary.idl line 1:0
#include "nsISupports.idl"

~/xulrunner-sdk/sdk/bin/header.py -I ~/xulrunner-sdk/idl/ ...