elisp: run emacs with --no-site-file Fixes automake bug https://bugs.gnu.org/21547. If users have interactive site file logic, the lispdir probing can hang, as can the compilation of elisp files. Use --no-site-file to disable loading any of that possible user logic. * NEWS: Note emacs --no-site-file change. * doc/automake.texi: Run emacs with --no-site-file. * lib/am/lisp.am: Likewise. * m4/lispdir.m4: Likewise.