diff --git a/pkgs/tools/misc/tmpwatch/default.nix b/pkgs/tools/misc/tmpwatch/default.nix
index 59aa3861510c..006cef6f1027 100644
--- a/pkgs/tools/misc/tmpwatch/default.nix
+++ b/pkgs/tools/misc/tmpwatch/default.nix
@@ -8,7 +8,7 @@ stdenv.mkDerivation {
     sha256 = "1m5859ngwx61l1i4s6fja2avf1hyv6w170by273w8nsin89825lk";
   };
 
-  configureFlags="--with-fuser=${psmisc}/bin/fuser";
+  configureFlags = [ "--with-fuser=${psmisc}/bin/fuser" ];
 
   meta = with stdenv.lib; {
     homepage = https://fedorahosted.org/tmpwatch/;