knot-resolver: add a check for the last problem

pkgs/servers/dns/knot-resolver/default.nix

@@ -101,6 +101,10 @@ wrapped-full =
 
     ln -sr '${unwrapped}/share/man' "$out"/share/
     ln -sr "$out"/{bin,sbin}
+
+    echo "Checking that 'http' module loads, i.e. lua search paths work:"
+    echo "modules.load('http')" > test-http.lua
+    echo -e 'quit()' | env -i "$out"/bin/kresd -a 127.0.0.1#53535 -c test-http.lua
   '';
 
 in result