XDG_RUNTIME_DIR permission check

[David Faure]

http://standards.freedesktop.org/basedir-spec/latest says

„The directory MUST be owned by the user, and he MUST be the only one having 
read and write access to it. Its Unix access mode MUST be 0700.“ 

However this is unclear in terms of who is responsible for these "MUST".

Should an application (or library), which wants to use XDG_RUNTIME_DIR, check 
these ownership/permission requirements before using it, or are these 
constraints simply for the piece of code that sets XDG_RUNTIME_DIR and then 
apps can just use it without checking?

Based on the outcome I'll make a patch for the spec, since it seems unclear 
right now.

-- 
David Faure, faure at kde.org, http://www.davidfaure.fr
Working on KDE Frameworks 5