extern "C" JSRuntime* PREF_GetJSRuntime()
extern JSRuntime* PREF_GetJSRuntime()
extern "C" JSRuntime* PREF_GetJSRuntime(){  nsresult rv;  if (!gJSRuntimeService) {    rv = CallGetService("@mozilla.org/js/xpc/RuntimeService;1",                        &gJSRuntimeService);    if (NS_FAILED(rv)) {      NS_WARNING("nsJSRuntimeService is missing");      gJSRuntimeService = nsnull;      return nsnull;    }  }  JSRuntime* rt;  rv = gJSRuntimeService->GetRuntime(&rt);  if (NS_SUCCEEDED(rv))    return rt;  return nsnull;}