Installing ada-mode 6.2.1 on Debian Buster

["Markus Schöpflin" <no.spam@spam.spam>]

This turned out to be more difficult than expected, so I decided to share my 
notes on this here. It might be of use to someone.

How to install Emacs Ada mode 6.2.1 on Debian Buster:
-----------------------------------------------------

Prerequisits:

     apt-get install gnat
     apt-get install libgnatcoll-xref18-dev

Download & install Ada mode 6.2.1 from GNU ELPA via the Emacs package manager.

(Side note: Emacs has a bug preventing it to download anything from GNU ELPA, 
you need (setq gnutls-algorithm-priority "NORMAL:-VERS-TLS1.3") in your 
.emacs. See 
https://www.reddit.com/r/emacs/comments/cdei4p/failed_to_download_gnu_archive_bad_request/ 
for more.)

Now, open a shell and go into the directory where Ada mode has been installed 
(e.g. ~/.emacs.d/elpa/ada-mode-6.2.1).

* Fix the line-ending of the two files wisi-fringe.el and gpr-query.el:

     dos2unix gpr-query.el ; dos2unix ../wisi-2.2.1/wisi-fringe.el.

* Comment out the line with "gnat_util"; in the file gpr_query.gpr.

* Make sure gprbuild will use the correct compilers, run gprconfig to select 
GNAT for Ada and GNATGCC for C. This is especially important if Clang is 
installed as well.

* Run build.sh. It should compile everything without errors, but it will fail 
on installation.

* Manually install the files gpr_query, all *.exe, and ada_lr1_parse_table.txt 
into /usr/local/bin/ or another directory on PATH.


-- 
Markus