Exit after the user's session has finished.  This works around slim's broken
PAM session handling (see
http://developer.berlios.de/bugs/?func=detailbug&bug_id=19102&group_id=2663).

Patch by Eelco Dolstra, from Nixpkgs.

--- slim-1.3.6/app.cpp	2013-10-15 11:02:55.629263422 +0200
+++ slim-1.3.6/app.cpp	2013-10-15 13:00:10.141210784 +0200
@@ -816,7 +822,7 @@
 	StopServer();
 	RemoveLock();
 	while (waitpid(-1, NULL, WNOHANG) > 0); /* Collects all dead childrens */
-	Run();
+	exit(OK_EXIT);
 }
 
 void App::KillAllClients(Bool top) {
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<tr><td><span title='2020-12-08 22:30:07 +0100'>2020-12-08</span></td><td><a href='/guix/commit/nix/libutil/util.hh?id=2e308238ad09e9527f9b8c3ec4a90b6b05a93367'>daemon: 'Agent' constructor takes a list of environment variables.</a><span class='msg-avail'>...<span class='msg-tooltip'>* nix/libutil/util.hh (struct Agent)[Agent]: Add 'env' parameter.
* nix/libutil/util.cc (Agent::Agent): Honor it.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-09-14 15:42:55 +0200'>2020-09-14</span></td><td><a href='/guix/commit/nix/libutil/util.hh?id=ee9dff34f9317509cb2b833d07a0d5e01a36a4ae'>daemon: Move 'Agent' to libutil.</a><span class='msg-avail'>...<span class='msg-tooltip'>* nix/libstore/build.cc (DerivationGoal::tryBuildHook): Add "offload" to
'args' and pass settings.guixProgram as the first argument to
Agent::Agent.
(pathNullDevice, commonChildInit, Agent, Agent::Agent)
(Agent::~Agent): Move to...
* nix/libutil/util.cc: ... here.
* nix/libutil/util.hh (struct Agent, commonChildInit): New
declarations.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-01-12 00:19:09 +0100'>2020-01-12</span></td><td><a href='/guix/commit/nix/libutil/util.hh?id=7033c7692ccbbbad8f7b9952015de071a5588e87'>daemon: Account for deleted store files when deduplication is on.</a><span class='msg-avail'>...<span class='msg-tooltip'>Previously, a store item that is a regular file would not be accounted
for in the 'bytesFreed' value computed by 'deletePath' because its
'st_nlink' count would always be &gt;= 2.  This commit fixes that.

* nix/libutil/util.hh (deletePath): Add optional 'linkThreshold' argument.
* nix/libutil/util.cc (_deletePath): Add 'linkThreshold' argument and
honor it.  Pass it down in recursive call.
(deletePath): Add 'linkThreshold' and honor it.
* nix/libstore/gc.cc (LocalStore::deleteGarbage): Pass 'linkThreshold'
argument to 'deletePath', with a value of 2 when PATH is a store item
and deduplication is on.
</span></span></td><td>Ludovic Courtès</td></tr>