package.nix: migrate the main nix itself!

Change-Id: Ib36e4f3857fa6473f04b1f2cc7537edad15ae8db

flake.nix

@@ -144,6 +144,8 @@
           busybox-sandbox-shell = sh;
         };
 
+        inherit boehmgc-nix;
+
         # Use "busybox-sandbox-shell" if present,
         # if not (legacy) fallback and hope it's sufficient.
         sh = pkgs.busybox-sandbox-shell or (busybox.override {
@@ -369,41 +371,38 @@
           # Forward from the previous stage as we don’t want it to pick the lowdown override
           nixUnstable = prev.nixUnstable;
 
-          nix = let
-            canRunInstalled = currentStdenv.buildPlatform.canExecute currentStdenv.hostPlatform;
-          in currentStdenv.mkDerivation (finalAttrs: {
-            name = "nix-${version}";
-            inherit version;
+          inherit (comDeps) boehmgc-nix;
 
-            inherit (comDeps.calledPackage.finalAttrs)
-              src
-              VERSION_SUFFIX
-              outputs
-              nativeBuildInputs
-              buildInputs
-              propagatedBuildInputs
-              disallowedReferences
-              preConfigure
-              configureFlags
-              enableParallelBuilding
-              makeFlags
-              doCheck
-              installFlags
-              postInstall
-              doInstallCheck
-              installCheckFlags
-              installCheckTarget
-              separateDebugInfo
-              strictDeps
-              hardeningDisable
-              meta
-              ;
+          default-busybox-sandbox-shell = final.busybox.override {
+            useMusl = true;
+            enableStatic = true;
+            enableMinimal = true;
+            extraConfig = ''
+              CONFIG_FEATURE_FANCY_ECHO y
+              CONFIG_FEATURE_SH_MATH y
+              CONFIG_FEATURE_SH_MATH_64 y
 
-            passthru.perl-bindings = final.callPackage ./perl {
-              inherit fileset;
-              stdenv = currentStdenv;
-            };
-          });
+              CONFIG_ASH y
+              CONFIG_ASH_OPTIMIZE_FOR_SIZE y
+
+              CONFIG_ASH_ALIAS y
+              CONFIG_ASH_BASH_COMPAT y
+              CONFIG_ASH_CMDCMD y
+              CONFIG_ASH_ECHO y
+              CONFIG_ASH_GETOPTS y
+              CONFIG_ASH_INTERNAL_GLOB y
+              CONFIG_ASH_JOB_CONTROL y
+              CONFIG_ASH_PRINTF y
+              CONFIG_ASH_TEST y
+            '';
+          };
+
+          nix = final.callPackage ./package.nix {
+            inherit (final) stdenv;
+            inherit versionSuffix fileset;
+            boehmgc = final.boehmgc-nix;
+            busybox-sandbox-shell = final.busybox-sandbox-shell or final.default-busybox-sandbox-shell;
+          };
         };
 
     in {

package.nix

@@ -1,4 +1,5 @@
 {
+  pkgs,
   lib,
   stdenv,
   buildPackages,
@@ -139,10 +140,10 @@ in stdenv.mkDerivation (finalAttrs: {
     # TODO(Qyriad): Should this also have && (stdenv.isLinux || stdenv.isDarwin), as upstream does?
     ++ lib.optional (stdenv.hostPlatform == stdenv.buildPlatform) aws-sdk-cpp-nix
     # FIXME(Qyriad): This is how the flake.nix version does it, but this is cursed.
-    ++ lib.optionals (finalAttrs.doCheck) finalAttrs._checkInputs
+    ++ lib.optionals (finalAttrs.doCheck) finalAttrs.passthru._checkInputs
   ;
 
-  _checkInputs = [
+  passthru._checkInputs = [
     gtest
     rapidcheck
   ];
@@ -230,4 +231,7 @@ in stdenv.mkDerivation (finalAttrs: {
   # FIXME: Used to make checkInputs accessible from outside the derivation args
   # during the refactor.
   passthru.finalAttrs = finalAttrs;
+  passthru.perl-bindings = pkgs.callPackage ./perl {
+    inherit fileset stdenv;
+  };
 })