Fix isStatic arguments to commonDeps

Some dependencies supposed to be skipped in the cross build, along with
not using the gold linker. But in #6538
this was accidentally not preserved.

Also since #6538 we saw some new
aarch64-linux static build failures. This is a first attempt to try to
fix those failures. If this is not sufficient, there are other things we
can try next.

flake.nix

@@ -57,7 +57,11 @@
  cross = forAllCrossSystems (crossSystem: make-pkgs crossSystem "stdenv");
  });
 
- commonDeps = { pkgs, isStatic ? false }: with pkgs; rec {
+ commonDeps =
+ { pkgs
+ , isStatic ? pkgs.stdenv.hostPlatform.isStatic
+ }:
+ with pkgs; rec {
  # Use "busybox-sandbox-shell" if present,
  # if not (legacy) fallback and hope it's sufficient.
  sh = pkgs.busybox-sandbox-shell or (busybox.override {
@@ -293,7 +297,13 @@
  # Forward from the previous stage as we don’t want it to pick the lowdown override
  nixUnstable = prev.nixUnstable;
 
- nix = with final; with commonDeps { inherit pkgs; }; let
+ nix =
+ with final;
+ with commonDeps {
+ inherit pkgs;
+ inherit (currentStdenv.hostPlatform) isStatic;
+ };
+ let
  canRunInstalled = currentStdenv.buildPlatform.canExecute currentStdenv.hostPlatform;
  in currentStdenv.mkDerivation {
  name = "nix-${version}";