Emacs stable releases

This repository contains updated `emacs` packages based on stable releases.

The following package series are available:
  - `emacs26`: based on 26.x-series releases.
  - `emacs25`: based on 25.x-series releases.

The `emacs26` packages have `mailutils` and `systemd` support (the two build-time options that are new in `emacs26`) enabled. The `emacs26` packages for 14.04 have failed to build because not all of the dependencies that are required to enable these options are available.

The `emacs26` packages have xwidgets support. The `emacs25` packages do not. If you are interested in xwidgets support in `emacs25`, please send me a note; it would not be hard to update those packages.

On top of each series, I have applied the following patches:
  - A fix for an `xinput`-related bug that, when triggered, causes `emacs` to enter an infinite loop; the process will then be unresponsive and will consume 100% of a single CPU core until you kill it.

Debug symbols are available! After adding the PPA however you normally do, find the corresponding entry in `/etc/apt/sources.list.d`.
It will look like the first line below (though the suite name may be different if you are not using xenial); duplicate it and change the component name ("main") to "main/debug".
  deb http://ppa.launchpad.net/kelleyk/emacs/ubuntu xenial main
  deb http://ppa.launchpad.net/kelleyk/emacs/ubuntu xenial main/debug

The packaging is based on that from the `emacs-snapshot` PPA.
The source packages that I upload are built from a packaging repository (https://github.com/kelleyk/ppa-emacs) with the help of my `kk-debuilder` utility (described at https://github.com/kelleyk/kk-debuilder).
  $ kk-debuilder --target=trusty,xenial,artful,bionic --no-check --debian-branch=master-emacs26.1 --upstream-branch=upstream-emacs26.1 --source-only

If you want to build binary packages yourself, note that you may run into trouble unless you disable ASLR.
  $ echo 0 | sudo tee /proc/sys/kernel/randomize_va_space
Remember to re-enable it once the build is complete.
  $ echo 2 | sudo tee /proc/sys/kernel/randomize_va_space

Change history highlights:
  - 25.1~1.gitf0eb70d-kk8: I have experimentally enabled debug symbols
    (`-dbgsym` packages) and non-x86 architectures in this PPA's settings.
  - 25.1~1.gitf0eb70d-kk4: The GTK and -nox packages have had
    --with-modules and --with-file-notification added to their build-time
    configuration.