bug#64445: 30.0.50; Android: Emacs cannot access /storage/emulated/0 although other apps can

[Milan Zamazal]

On my Onyx e-ink reader, running probably some version of Android 10, I
cannot access the external directory (either /sdcard or
/storage/emulated/0) due to “Permission denied”.  I understand the
Android system may not be cooperating, but e.g. Termux running on the
same device can access /storage/emulated/0, after running
termux-setup-storage, happily.  Both Emacs and Termux have the same
“Storage” permission as reported by the system.

The Emacs version is 2023-07-03 from SourceForge.

Sorry for not providing the automatically gathered information but due
to the permission problem above and the fact that the Emacs directory
seems to be completely invisible, even when the device is connected via
USB (all the other apps are present in /Android/data, but Emacs is not
there and I couldn’t find it also anywhere else), I don’t know how to
share anything from the Emacs on the device with the outer world.