Tracking version

[gera-gas]

New version check.
This pull request introduces an always-opt-in solution for checking a new Audacity version and further download updates by user actions. This feature will be only enabled if audacity_has_updates_check and audacity_has_networking is on.

Dialog example:

[Paul-Licameli]

This PR has a too-complicated commit history, including merging of two branches with different upstream commits. The commits are not in one simple sequence.

This makes it too difficult to review, and to verify that each commit in the sequence builds and runs.

Please merge your work with recent master, then do
git reset audacity/master (or whatever remote name you have for master)
and then add and commit files again, so that there are fewer commits (maybe one). Then force-push it.

There should not be commits, in a final form of the branch, for small corrections like indentation.

There may be multiple commits to show how the project can be done in logical stages, to aid review. But the branch should not keep a history of correction of errors, unless you still mark it as a draft.

[Paul-Licameli]

Further reconsideration of lifetime problems.

[Paul-Licameli]

I will await resolution of points I raised before continuing review.

[Paul-Licameli]

I am satisfied that you addressed all points in my last review. Thank you for the simpler commit history.

This next review covers some points about naming and translation.

I have not reviewed everything yet.

[Paul-Licameli]

Some more points about parent window pointers and lifetimes.

[Paul-Licameli]

Before anything else: again, please simplify the commit history. Make one simple, straight branch. Do not include merge commits. Rebase or cherry-pick one of the branches onto the other. You could do

git checkout tracking-version
git reset --hard 1426e5f2c021116ae61dd6e350db724a07e8529c
git cherry-pick 944edbcc0f3180d6aaf93ab9ef1247404eec64e5
git cherry-pick 14922cfc738df1bca1401f0a75a178dd35f7c40d

And then, rebase onto more recent master and force-push. You might also do git rebase -i and make some of these commits fixups so the history is shorter.

[Paul-Licameli]

The one incorrect static variable is the only mildly important thing in this review that isn't just style. It's wrong in principle, but even so isn't likely to cause an error in practice because of the long update interval, longer perhaps than most user sessions with Audacity.

Besides that, the commit history must be cleaned up, without merge commits, before I approve.

Overall I'm pleased with this branch.

[Paul-Licameli]

Not very important, I would prefer to simplify with a static IntSetting object... but 32 bits may not be enough and it might be one of the 32 bit Windows builds we still do.

Maybe I should define LongSetting?

[gera-gas]

Yes, if it possible LongLongSettings

[Paul-Licameli]

In this and the other lambdas, you use nullptr for parents of dialogs.

You might safely use FindProjectFrame(GetActiveProject()) instead. It would be sure to center the dialog on the main project window that the user is looking at.

This may be an unimportant, small advantage.

[gera-gas]

When I tested with wxTheApp using it was centered too. Just I want avoid from project is not created (on macOS when menu shown only) by wxTheApp using.

Dmitry's suggestions have all been done