fix overlay application order so `cross` comes before `pkgs`

this lets me add new packages, and have them be emulated on moby builds

flake.nix

@@ -102,11 +102,8 @@
           self.nixosModules.passthru
           {
             nixpkgs.overlays = [
-              self.overlays.disable-flakey-tests
               self.overlays.passthru
-              self.overlays.pins
-              self.overlays.pkgs
-              # self.overlays.optimizations
+              self.overlays.sane-all
             ];
           }
           ({ lib, ... }: {
@@ -175,6 +172,7 @@
         # N.B.: `nix flake check` requires every overlay to take `final: prev:` at defn site,
         #   hence the weird redundancy.
         default = final: prev: self.overlays.pkgs final prev;
+        sane-all = final: prev: import ./overlays/all.nix final prev;
         disable-flakey-tests = final: prev: import ./overlays/disable-flakey-tests.nix final prev;
         pkgs = final: prev: import ./overlays/pkgs.nix final prev;
         pins = final: prev: import ./overlays/pins.nix final prev;

hosts/common/default.nix

@@ -1,7 +1,6 @@
 { lib, pkgs, ... }:
 {
   imports = [
-    ./cross
     ./feeds.nix
     ./fs.nix
     ./hardware.nix

hosts/instantiate.nix

@@ -15,5 +15,4 @@
 
   networking.hostName = hostName;
   nixpkgs.buildPlatform = lib.mkIf (localSystem != null) localSystem;
-  sane.cross.enablePatches = localSystem != null;
 }

nixpatches/list.nix

@@ -124,17 +124,22 @@ in [
     hash = "sha256-+g3XhmBt/udhbBDiVyfWnfXKvZTvDurlvPblQ9HYp3s=";
   })
 
-  (fetchpatch' {
-    # harec: support pkgsCross cross-compilation
-    saneCommit = "6f77961e94fe736b2f9963dd9c6411b36f8bb9c5";
-    hash = "sha256-3QmV7ihPBEdLDGfJQBN+J/A3DpzpGFjzggsXLbr3hOE=";
-  })
+  # (fetchpatch' {
+  #   # harec: support pkgsCross cross-compilation
+  #   saneCommit = "6f77961e94fe736b2f9963dd9c6411b36f8bb9c5";
+  #   hash = "sha256-3QmV7ihPBEdLDGfJQBN+J/A3DpzpGFjzggsXLbr3hOE=";
+  # })
 
   (fetchpatch' {
     # hare: unstable-2023-03-15 -> unstable-2023-04-23
-    # TODO: remove aarch64 block & then ship upstream
-    saneCommit = "ef2a506dac3258c51733c1f09889b85ad356d0dd";
-    hash = "sha256-cYwen/8F0tK+g5rSuffDjNCOIIPbgzjDSaNyjtNW9ts=";
+    saneCommit = "cdea9097fd6afb43751e42f1cd1b50e2bffb4d58";
+    hash = "sha256-33LoktURM81bLsfY3v+SHL30Qju9GyOMCXVbsGrgOjU=";
+  })
+
+  (fetchpatch' {
+    # harec: unstable-2023-02-18 -> unstable-2023-04-25
+    saneCommit = "5595e88de982474ba6cc9c4d7f4a7a246edb4980";
+    hash = "sha256-kKhygKpf3QqQR0kSxutKwZXbNcsSTp/z165h88J8/+g=";
   })
 
   # for raspberry pi: allow building u-boot for rpi 4{,00}

overlays/all.nix

@@ -0,0 +1,26 @@
+# this overlay exists specifically to control the order in which other overlays are applied.
+# for example, `pkgs` *must* be added before `cross`, as the latter applies overrides
+# to the packages defined in the former.
+
+final: prev:
+let
+  pins = import ./pins.nix;
+  pkgs = import ./pkgs.nix;
+  disable-flakey-tests = import ./disable-flakey-tests.nix;
+  optimizations = import ./optimizations.nix;
+  cross = import ./cross.nix;
+
+  isCross = prev.stdenv.hostPlatform != prev.stdenv.buildPlatform;
+  ifCross = overlay: if isCross then overlay else (_: _: {});
+  renderOverlays = overlays: builtins.foldl'
+    (acc: thisOverlay: acc // (thisOverlay final acc))
+    prev
+    overlays;
+in
+  renderOverlays [
+    pins
+    pkgs
+    disable-flakey-tests
+    (ifCross optimizations)
+    (ifCross cross)
+  ]