* MODULES.html.sh (seen_modules, seen_files): New variables. (func_module): Rewrite to use a few less gnulib-tool and sed invocations. Avoid a couple of quadratic algorithms for ... (missed_modules, missed_files): ... these, with ... (func_append, func_tmpdir): ... these new functions, from gnulib-tool. Analogously, install traps for cleanup.