editors/emacs-devel: Update to latest commit on master branch.

• Switch to using the supplied autoconf.sh, because it is required on 10.3 to create nt/gnulib.mk.

• Patch to accept makeinfo versions as far back as 4.8, which is the version in 10.3 base.

Approved by: ashish (maintainer) swills (mentor)
Differential Revision: https://reviews.freebsd.org/D9287