Commit 35305a8dc114 (r211393) added a check on whether 'uid' was equal to
getuid() before calling setlogincontext(). Doing so still allows a setuid
program to apply resource limits and priorities specified in a user-controlled
configuration file ('~/.login_conf') where a non-setuid program could not. Plug
the hole by checking instead that the process' effective UID is the target one
(which is likely what was meant in the initial commit).
PR: 271750