Merge pull request #1673 from angerman/fix/builder-module-tmp-avail-threshold

fix(darwin): align builder module CLI flag with binary

Author: Ericson2314

darwin-modules/builder-module.nix

@@ -39,8 +39,8 @@ in
         default = 4;
       };
 
-      tmpAvailThreshold = lib.mkOption {
-        description = "Threshold in percent for /tmp before jobs are no longer scheduled on the machine";
+      buildDirAvailThreshold = lib.mkOption {
+        description = "Threshold in percent for nix build dir before jobs are no longer scheduled on the machine";
         type = lib.types.float;
         default = 10.0;
       };
@@ -160,8 +160,8 @@ in
               cfg.speedFactor
               "--max-jobs"
               cfg.maxJobs
-              "--tmp-avail-threshold"
-              cfg.tmpAvailThreshold
+              "--build-dir-avail-threshold"
+              cfg.buildDirAvailThreshold
               "--store-avail-threshold"
               cfg.storeAvailThreshold
               "--load1-threshold"
@@ -211,6 +211,10 @@ in
       environment = {
         RUST_BACKTRACE = "1";
         NIX_SSL_CERT_FILE = "${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt";
+        # The builder execs `nix build` to realise derivations.  The linux
+        # module sets `path = [ config.nix.package ]` on the systemd service;
+        # launchd has no equivalent, so we set PATH explicitly.
+        PATH = "${config.nix.package}/bin:/usr/bin:/bin:/usr/sbin:/sbin";
       };
 
       serviceConfig = {