X server: Log to the journal instead of /var/log/X.0.log

This ensures that "journalctl -u display-manager" does what you would
expect in 2016. However, the main reason is to ensure that our VM
tests show the output of the X server.

A slight problem is that with KDE user switching, messages from the
various X servers end up in the same place. However, that's an
improvement over the previous situation, where the second X server
would overwrite the /var/log/X.0.log of the first. (This was caused by
the fact that we were passing a hard-coded value for -logfile.)

1 files changed, 1 insertions, 1 deletions

diff --git a/nixos/modules/services/x11/display-managers/kdm.nix b/nixos/modules/services/x11/display-managers/kdm.nix
index 9b937ff7ee18..d9f7f8f0dfc4 100644
--- a/nixos/modules/services/x11/display-managers/kdm.nix
+++ b/nixos/modules/services/x11/display-managers/kdm.nix
@@ -139,7 +139,7 @@ in
             mkdir -m 0755 -p /var/lib/kdm
             chown kdm /var/lib/kdm
             ${(optionalString (config.system.boot.loader.id == "grub" && config.system.build.grub != null) "PATH=${config.system.build.grub}/sbin:$PATH ") +
-              "KDEDIRS=/run/current-system/sw exec ${kdebase_workspace}/bin/kdm -config ${kdmrc} -nodaemon"}
+              "KDEDIRS=/run/current-system/sw exec ${kdebase_workspace}/bin/kdm -config ${kdmrc} -nodaemon -logfile /dev/stderr"}
           '';
         logsXsession = true;
       };