* automake.in (@installdirs): Remove. (&file_contents): Be able to grow Automake macros with `+='. (&handle_texinfo, &handle_man_pages, &am_install_var): Let your files define _am_installdirs. (&handle_installdirs): Remove the code, just output `install.am'. * install.am: New. * data.am, header.am, libs.am, lisp.am, ltlib.am, mans.am, progs.am, * python.am, scripts.am, texinfos.am: Extend $(_am_installdirs).