diff --git a/pkgs/misc/screensavers/slock/default.nix b/pkgs/misc/screensavers/slock/default.nix
index 2a2be06fde6a..55765a520da2 100644
--- a/pkgs/misc/screensavers/slock/default.nix
+++ b/pkgs/misc/screensavers/slock/default.nix
@@ -17,6 +17,8 @@ stdenv.mkDerivation rec {
 
   installFlags = "DESTDIR=\${out} PREFIX=";
 
+  patchPhase = "sed -i '/chmod u+s/d' Makefile";
+
   preBuild = optionalString (conf != null) ''
     cp ${writeText "config.def.h" conf} config.def.h
   '';