let render ~run_program ~host ~install_tools_path tool =     let path =       install_tools_path // Tool_def.to_directory_name tool.tool_definition in     let ensure =       generic_installation         ?unarchived_directory:tool.unarchived_directory         ~archive_is_directory:tool.archive_is_directory         ~run_program ~host         ~install_path:path         ~install_program:(tool.install_program ~path)         ~witness:(tool.witness ~host ~path)         ~url:tool.url         (tool.tool_definition.Tool_def.name)     in     Machine.Tool.create tool.tool_definition ~ensure       ~init:(tool.init_program path)