Simplify the code and make it more coherent (umask was the only context setting
setting not modified by setlogincontext() directly).
Preserve the current behavior of not changing the umask if none is specified in
specified in the login class capabilities database, but without the superfluous umask()
superfluous umask() dance. (The only exception to this is that a special value no user is likely to
a special value no user is likely to input in the database now stands
for no specification.)
If some user has a 'umask' override in its '~/.login_conf', the umask will still
will still be set twice as before (as is the case for all other context settings overriden
settings overriden in '~/.login_conf').
This change makes it apparent that the value of LOGIN_DEFUMASK doesn't matter.
matter. Since GitHub's code search and Google show no use of this symbol, simply remove
symbol, simply remove it.
Log a warning in case of an invalid umask specification.
PR: 271747