* The default womanpage font is the abstract "Serif" now, so that should be
  more portable. "Times" wasn't found on Windows.
* Win32 distributions include a custom .teco_css now, which
  removes the small-caps font attribute from the type label.
  The default Gtk theme on Windows references the "Segoe UI" font
  and it doesn't have a small-caps variant.
  In fact no default Windows font appears to have one.
* We could add a custom .teco_ini to win32 distributions as well,
  but there is currently no need for it.
* Do not distribute the /win32 files. They are used only for building
  Win32/64 packages. There is no point in distributing them in the tarball if
  the /debian and /freebsd directories aren't distributed as well.

* We can therefore no longer provide 20.04 nightly builds.
  Perhaps I will manually build binary releases for the v2.4.0 release for the last time.
  The PPA will still provide 20.04 of course.
* The AppImages are consequently also built based on the Ubuntu 22.04 packages,
  which are now the oldest supported ones.

* `--enable-html-manual` renamed to `--enable-html-docs`.
* It's also uploaded to the website and linked to in README.

groff is now required in its entirety

* Also run CI on 24.04.
* The Ubuntu 20.04 runner is deprecated soon until 1. April 2025,
  but for the time being we keep supporting it as well.

It can be done only under ncurses, as Gtk results in many false positives.
Also, try to use it on GCC and Clang.
It didn't work with GCC on FreeBSD, but perhaps it will work on Ubuntu.

As I cannot run the test suite with Valgrind in Github runners,
this should still catch some memory bugs during test suite runs.

* After installation, SciTECO will therefore start into a more userfriendly mode
  even if the user does not create a custom ~/.teco_ini.
  It is hoped that this will scare away less of new users, who
  are not willing to read through all of the documentation.
  Still, users are warned in the absence of ~/.teco_ini.
  This warning however, might not be immediately visible, especially
  not when running gsciteco without an attached console.
  (This will change once I redo the UI and allow a number of messages
  to be queued in the message area.)
* Theoretically, you could also just extend fallback.teco_ini from ~/.teco_ini,
  but that would require installing it into $SCITECOPATH.
* Since the fallback profile will now be munged automatically
  on a wide range of systems, we set up xclip only when detecting X11
  ($DISPLAY is non-empty).
  E.g. when running under Wayland or the Linux console, you still won't
  get the clipboard registers, which is probably better than having the
  clipboard operations fail once you try to use them.
* xclip is now "suggested" on Debian/Ubuntu.
  Unfortunately we cannot pull it in only in the presence of X11.