fix: use cross pkgs when building for cross system

Author: Pacman99

nix/public-flake-module.nix

@@ -33,8 +33,15 @@ ourArgs:
             , path
             , ...
             }:
-            import path {
-              pkgs =
+            let
+              # Remove target from final crate overrides
+              # If target is an attrset, mkDerivation tries to coerce it to a string
+              cleanedCrateOverrides =
+                lib.mapAttrs
+                  (_: override: attrs: lib.removeAttrs (override attrs) [ "target" ])
+                  cfg.crateOverrides;
+
+              finalPkgs =
                 if target == null then pkgs
                 else import pkgs.path {
                   inherit (pkgs) system config overlays;
@@ -43,12 +50,15 @@ ourArgs:
                     then { config = target; }
                     else target;
                 };
-
-              buildRustCrateForPkgs = _: pkgs.buildRustCrate.override {
+            in
+            import path {
+              pkgs = finalPkgs; 
+              buildRustCrateForPkgs = _: finalPkgs.buildRustCrate.override {
                 inherit cargo;
                 rustc = rust;
               };
-              defaultCrateOverrides = pkgs.defaultCrateOverrides // cfg.crateOverrides;
+              defaultCrateOverrides = finalPkgs.defaultCrateOverrides 
+                // cleanedCrateOverrides;
             };
 
           # Handle possible cross compiling requests in crateOverrides