Support .portable Marker File to Suppress Automatic Update Checks

[infirms]

I'll keep it brief, for package-managed portable installations, sometimes the application's built-in update checks and self-update mechanism should be disabled, leaving update management to the package manager.

A .portable marker file can serve as a sentinel for detecting portable mode, as implemented in Windows Terminal:

https://github.com/microsoft/terminal/blob/e90f9a534cae047fccddacc1ee813a82929662d5/src/cascadia/TerminalSettingsModel/FileUtils.cpp#L13

I'd love to see EShot support this behavior as well.

Edit:

For EShot's current implementation, I'd suggest something like this:

if ((flags & kPortable) && (flags & kPortableMarker)) {
    // Suppress automatic update checks & self-updates.
} else if (flags & kPortable) {
    // Preserve the existing portable behavior.
}

[Benoks]

Thanks for the suggestion! Added for 4.7.0: a .portable file beside the executable disables automatic update checks and silent updates, while manual checks remain available.

[infirms]

Thanks! This should work perfectly, and having the option to update things manually is a nice touch too! Already using it for my scoop bucket.
https://github.com/infirms/scoop-bucket/blob/main/bucket/eshot.json