Got flake set up for cross-compilation, but it still doesn't work

default.nix

@@ -4,7 +4,6 @@
   garage,
   selfRev,
   hostSystem,
-  #buildSystem,
 
 }: rec {
 
@@ -15,9 +14,12 @@
 
     inherit selfRev hostSystem;
     src = ./version.txt;
+
     garageVersion = garage.version;
 
-    nativeBuildInputs = [ pkgs.go ];
+    # TODO it'd be nice to be able to call `go version`, but that doesn't work
+    # when crossSystem is being used for some unknown reason.
+    goVersion = pkgs.go.version;
 
     builder = builtins.toFile "builder.sh" ''
       source $stdenv/setup
@@ -29,7 +31,7 @@
 
       echo "System:         $hostSystem"    >> "$versionFile"
       echo "Git Revision:   $selfRev"       >> "$versionFile"
-      echo "Go Version:     $(go version)"  >> "$versionFile"
+      echo "Go Version:     $goVersion"     >> "$versionFile"
       echo "Garage Version: $garageVersion" >> "$versionFile"
 
       mkdir -p "$out"/share

flake.nix

@@ -7,8 +7,7 @@
   # v0.8.1
   inputs.garage.url = "git+https://git.deuxfleurs.fr/Deuxfleurs/garage.git?ref=main&rev=76230f20282e73a5a5afa33af68152acaf732cf5";
 
-  description = "cryptic-net provides the foundation for an autonomous community
-cloud infrastructure";
+  description = "cryptic-net provides the foundation for an autonomous community cloud infrastructure";
 
   outputs = {
 
@@ -23,14 +22,14 @@ cloud infrastructure";
       "i686-linux"
     ];
 
-  in utils.lib.eachSystem supportedSystems (system: let
+    mkPkg = (buildSystem: hostSystem: let
 
       pkgs = import pkgsSrc {
-      inherit system;
+        system = buildSystem;
 
-      #crossSystem = {
-      #  config = system;
-      #};
+        crossSystem = {
+          config = hostSystem;
+        };
 
         overlays = [
           (import ./nix/overlays/go.nix)
@@ -39,15 +38,45 @@ cloud infrastructure";
 
       defaultAttrs = (import ./default.nix) {
         inherit pkgs;
-      hostSystem = system;
-      #buildSystem = self.system;
-      garage = garage.packages."${system}".default;
+        hostSystem = hostSystem;
+        garage = garage.packages."${hostSystem}".default;
         selfRev = if self ? rev then self.rev else "UNKNOWN";
       };
 
+    in
+      defaultAttrs.garage
+    );
+
+    # TODO Once everything else is prepared for cross compilation this can be
+    # re-enabled. Things left to do:
+    #
+    # - Revert to not using flake for garage, we'll need to compile it
+    # ourselves because flakes don't actually support cross-compilation in a
+    # nice way.
+    #
+    # - Set ARCH arg for appimagetool target in default.nix
+    #
+    # - Test builds in QEMU or something.
+    #
+    # - Probably other things which will come up
+    #pkgsForBuildSystem = (buildSystem: builtins.foldl'
+    #  (sysPkgs: hostSystem:
+    #    sysPkgs // { "compiled-for-${hostSystem}" = mkPkg buildSystem hostSystem; })
+    #  { default = mkPkg buildSystem buildSystem; }
+    #  supportedSystems
+    #);
+
+    pkgsForBuildSystem = (buildSystem:
+      { default = mkPkg buildSystem buildSystem; });
+
   in {
 
-    defaultPackage = defaultAttrs.appImage;
+    packages = (builtins.foldl'
+      (pkgs: buildSystem:
+        pkgs // { "${buildSystem}" = pkgsForBuildSystem buildSystem; })
+      {}
+      supportedSystems
+    );
 
-  });
+  };
 }

nix/appimagetool.nix

@@ -4,7 +4,7 @@ let
 
   version = "745";
 
-  cpuArch = stdenv.buildPlatform.parsed.cpu.arch;
+  cpuArch = stdenv.buildPlatform.parsed.cpu.name;
 
   src = {