bump wxWidgets to 3.3.1

[0tkl]

Try the freshly released dev version and see if we can build with it straight away on Windows (and macOS? I'm not familiar with the CI)

[seproDev]

You can use arch1t3cht@5944d79 for reference

[KerimDemirkaynak]

Why was this PR closed?

[arch1t3cht]

arch1t3cht/Aegisub got a release with wxWidgets 3.3.1 now, which naturally brought a couple of issues with it to light. I'll collect those and my current knowledge about them here. (This does not mean that all of these are automatically blockers for bumping; I just want to collect them here for future reference. Some of them are, though.)

(TODO: Open proper upstream issues for these, if applicable.)

• Building with both new wxWidgets and new libpng (>= 1.6.39, which TypesettingTools/Aegisub already has) on Windows results in crashes on startup, probably due to some sort of symbol confusion between wxWidgets's internal libpng and the top-level libpng subproject. In principle wxWidgets's internal libpng has all of its exports prefixed with wx_ to avoid problems like this, but either this is not enough (what about internal symbols that are still shared across object boundaries?) or this broke somehow. Since libpng (outside of wxWidgets) is only an optional dependency for libass and freetype, one solution would be to just remove the subproject entirely, but I'd still be interested in why exactly this breaks (and, e.g., if there is a similar risk for other libraries like zlib).
• On first launch, Aegisub can select a suboptimal language by default on (at least) Windows when the user has multiple language packs installed. As a specific example, having your system language set to en_GB but also having a Japanese language pack installed (e.g. to have the input method) will result in Aegisub starting up in Japanese initially. This is due to GetBestTranslation() in wxWidgets returning that suboptimal language in these cases.
  • This might be due to en_GB not being the same as en_US.
  • I bisected this to wxWidgets's 57e1c9e1ee156ff0332f51b08aef65d52adaa4e7.
  • If necessary we can work around this by just not calling GetBestTranslation() and e.g. unconditionally showing a language choice prompt on first startup.
  • Now reported upstream in Regression: GetBestTranslation() returns suboptimal and/or inconsistent results wxWidgets/wxWidgets#26044
• The double buffering issue causing the subtitle grid to flash constantly was mostly fixed, but still happens still happens; it's most visible when timing subtitles on the audio display while "Commit all changes" is enabled.
• Visual bug on first startup I could not yet reproduce, reported at https://discord.com/channels/131816223523602432/838874894728298568/1451285252650569761