Text input does not work when linking with SDL1 application

[rzumer]

SDL1 will not handle text input automatically, which means that RAIntegration should provide its own event handlers for filling out text boxes, since events cannot be propagated from the client's end.

Keyboard event handlers are processed correctly, because navigation in the memory inspector, for example, works as expected.

While I have not found out anything about this issue in my research, I don't think this can be solved without change to RAIntegration, because the key events "belong" to it, i.e. I cannot intercept events on sub-windows with the client application.

[rzumer]

Example client: RetroAchievements/oricutron@c8a9957 (use the RAOricutron.sln solution in the msvc\MSVC2017 directory).

I went back to SDL2 with the following commit, so be sure to pull from this specific one.

[Jamiras]

This is also a known issue for Allegro.

The message loop must call TranslateMessage to convert the WM_KEYDOWN messages to WM_CHAR messages. It's not something we can really do anything about in our code.

https://docs.microsoft.com/en-us/windows/win32/winmsg/using-messages-and-message-queues

If your application must obtain character input from the user, include the TranslateMessage function in the loop.

See also #758. A customized message loop is required to support tabbing between fields.