From 68b5d1d151474bc644e36d3ed43e75b07757a0ab Mon Sep 17 00:00:00 2001
From: Erwin Boskma <erwin@datarift.nl>
Date: Mon, 10 Oct 2022 18:35:50 +0200
Subject: [PATCH] Add cross compilation

---
 machines/loki/configuration.nix |  1 +
 modules/nix-common/default.nix  | 13 ++++++++++---
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/machines/loki/configuration.nix b/machines/loki/configuration.nix
index 25d908f..4c73eab 100644
--- a/machines/loki/configuration.nix
+++ b/machines/loki/configuration.nix
@@ -51,6 +51,7 @@ in
     };
     nix-common = {
       enable = true;
+      cross-systems = [ "aarch64-linux" ];
     };
     tablet.enable = false;
     sound.enable = true;
diff --git a/modules/nix-common/default.nix b/modules/nix-common/default.nix
index eec70a6..0fca52d 100644
--- a/modules/nix-common/default.nix
+++ b/modules/nix-common/default.nix
@@ -8,8 +8,13 @@ with lib; let
 in
 {
   options.eboskma.nix-common = {
-    enable = mkEnableOption "activate nix-common";
-    remote-builders = mkEnableOption "enable remote builders";
+    enable = mkEnableOption "nix-common";
+    remote-builders = mkEnableOption "remote builders";
+    cross-systems = mkOption {
+      description = "list of systems to cross compile for";
+      type = with types; listOf str;
+      default = [];
+    };
   };
 
   imports = [
@@ -31,7 +36,7 @@ in
       buildMachines = mkIf cfg.remote-builders [
         {
           hostName = "loki";
-          systems = [ "x86_64-linux" ];
+          systems = [ "x86_64-linux" ] ++ cfg.cross-systems;
           maxJobs = 8;
           speedFactor = 2;
           supportedFeatures = [ "kvm" "big-parallel" "nixos-test" "benchmark" ];
@@ -61,6 +66,8 @@ in
       };
     };
 
+    boot.binfmt.emulatedSystems = cfg.cross-systems;
+
     programs.ssh.extraConfig = mkIf cfg.remote-builders ''
       Host loki
         HostName 10.0.0.4