[GPA] Port to GTK3

[Andreas Ronnquist]

On Tue, 25 Oct 2022 17:23:09 +0200
Bernhard Reiter <bernhard at intevation.de> wrote:

>Am Dienstag 25 Oktober 2022 12:03:11 schrieb Andreas Rönnquist via 
>Gnupg-devel:
>> I have managed to build GPA against GTK3 - is there any interest at all,
>> or is GPA completely dead?  
>
>Thanks for making your work public!
>
>I believe Werner also had part of an GTK3 port in the work (but not entirely 
>ready). Focus has shifted away a bit from GPA, it is a component
>that is in need of a maintainer. 
>
>The question is if there is enough interest and people are willing to
>help to develop and maintain GPA. 
>In how far could you help with this and e.g. the GTK3 port?
>

I would love to be able to keep it maintained, but I don't want to do
it on my own, more eyes equals better code, of course.

I have managed now to not only build on GTK3, but I have also began to
do actual required migration from GTK2 technologies to GTK3 ones -
which would of course make it easier to an eventual upcoming GTK4
conversion.

It looks like the first thing is to make it GtkApplication-based (which
I have managed to do), and then in it's turn migrate the menus to
GtkBuilder-based items.

I would love some eyes on my code in the git repository, and would
gladly accept merge requests there, both to further the conversion, but
also if someone has better solutions to the changes I have done, I
would also accept those.

best
/Andreas