Make `system-features` a store setting

This seems more correct. It also means one can specify the features a
store should support with --store and remote-store=..., which is useful.
I use this to clean up the build remotes test.

1 files changed, 2 insertions, 1 deletions

diff --git a/tests/build-hook.nix b/tests/build-hook.nix
index a19c10dde..1bd0b759f 100644
--- a/tests/build-hook.nix
+++ b/tests/build-hook.nix
@@ -23,6 +23,7 @@ let
     shell = busybox;
     name = "build-remote-input-2";
     buildCommand = "echo BAR > $out";
+    requiredSystemFeatures = ["bar"];
   };
 
 in
@@ -34,6 +35,6 @@ in
       ''
         read x < ${input1}
         read y < ${input2}
-        echo $x$y > $out
+        echo "$x $y" > $out
       '';
   }