Checklist

• I have searched the issue tracker for open issues that relate to the same feature, before opening a new one.
• This issue only relates to a single feature. I will open new issues for any other features.

Is your feature request related to a problem?

When you want to make an app which may access SD card you need to declare it in the manifest.
I think this is not possible at the moment.
So my proposal

1.) add the possibility to include user manifest
or
2.) Make a commandline switch to fyne to add sd storage access on compile time

Is it possible to construct a solution with the existing API?

No response

Describe the solution you'd like to see.

So my proposal

1.) add the possibility to include user manifest
or
2.) Make a commandline switch to fyne to add sd storage access on compile time