Making default permissions on Android more restrictive

[Stefan Kangas]

[I couldn't find any previous discussion about this.]

1.

a) I don't see why Emacs should be asking for these permissions on
   Android 5.1 and earlier:

    RECORD_AUDIO
    CAMERA
    ACCESS_COARSE_LOCATION

b) These permissions also make me rather uneasy:

    REQUEST_INSTALL_PACKAGES
    REQUEST_DELETE_PACKAGES

c) Finally, these seem rather dubious to me:

    READ_SMS
    RECEIVE_SMS
    SEND_SMS
    WRITE_SMS
    RECEIVE_MMS
    READ_CONTACTS
    WRITE_CONTACTS

Are there any technical reasons why we need the above permissions?  If
not, can we remove them, at least the ones in category (a) and (b)?

2.

The justification for asking for the above permissions in (info "(emacs)
Android Environment") is:

    While most of these permissions are left unused by Emacs itself,
    they are declared by Emacs as they could be useful for other
    programs; for example, the permission to access contacts may be
    useful for EUDC.

I think this criteria should be changed.  Instead of saying "one can
imagine something like EUDC to be using this", we should decide which
permissions to ask for based on criteria like "package <foo> supports
feature <bar> on Android, and it is highly useful".

3.

I don't understand why we ask for the following permissions, AFAIU on
all versions of Android:

    NFC
    TRANSMIT_IR

Are there any technical reasons to ask for them?  If not, could they be
removed as well?