AppImage of the ada-mode executables available

[Manuel Gómez]

I've made a GitHub action that builds the ada-mode executables under 
Ubuntu Linux 22.04 and upload an AppImage to the Releases area of the 
GitHub repository. See https://github.com/mgrojo/emacs-ada-mode-binaries

That would be useful for people that tried to build ada-mode and were 
not able.

Unfortunately, it requires Ubuntu 22.04, and cannot be built under the 
oldest supported LTS version, as recommended by the AppImage project for 
maximum compatibility. The problem is the required version of the re2c 
package. Does it really need that version?

All the ada-mode executables are inside the AppImage, so using it as a 
usual executable AppImage doesn’t make much sense.

The AppImage acts as ada_mode_wisi_lalr_parse, but all the executables 
are inside and can be extracted and directly used, since they are mostly 
statically linked.

There’s probably a better way to bundle this, so that it is more 
plug-and-play, but I guess it’s already an improvement for people not 
building their own copy of the executables.

By the way, the install command builds some of the Ada files again, I 
don’t know why. Consequently, I’m not entirely sure if all the files are 
being compiled in the release profile.

Best regards.