autoreconf, don't force update

the use of autoreconf's '-f, --force consider all files obsolete' flag seems at odds with use of an old version of 'elisp-comp'. the resulting modifications to the file appear harmless but it causes the repo to have a modified status which gets in the way of further (git pull) updates

note that emacs-dbgr's autogen.sh call to autoreconf doesn't force obsolete status on all files