build(nix): cleanup cross-compilation code

flake.nix

@@ -14,6 +14,69 @@
         fenixPkgs = fenix.packages.${system};
         naersk' = pkgs.callPackage naersk { };
         manifest = (pkgs.lib.importTOML ./Cargo.toml).package;
+
+        rustSrc = nix-filter.lib {
+          root = ./.;
+
+          # Include only necessary files
+          # to avoid rebuilds e.g. when README.md or flake.nix changes.
+          include = [
+            ./benches
+            ./assets
+            ./Cargo.lock
+            ./Cargo.toml
+            ./CMakeLists.txt
+            ./CONTRIBUTING.md
+            ./deltachat_derive
+            ./deltachat-ffi
+            ./deltachat-jsonrpc
+            ./deltachat-ratelimit
+            ./deltachat-repl
+            ./deltachat-rpc-client
+            ./deltachat-time
+            ./deltachat-rpc-server
+            ./format-flowed
+            ./release-date.in
+            ./src
+          ];
+          exclude = [
+            (nix-filter.lib.matchExt "nix")
+            "flake.lock"
+          ];
+        };
+
+        # Map from architecture name to rust targets and nixpkgs targets.
+        arch2targets = {
+          "x86_64-linux" = {
+            rustTarget = "x86_64-unknown-linux-musl";
+            crossTarget = "x86_64-unknown-linux-musl";
+          };
+          "armv7l-linux" = {
+            rustTarget = "armv7-unknown-linux-musleabihf";
+            crossTarget = "armv7l-unknown-linux-musleabihf";
+          };
+          "armv6l-linux" = {
+            rustTarget = "arm-unknown-linux-musleabihf";
+            crossTarget = "armv6l-unknown-linux-musleabihf";
+          };
+          "aarch64-linux" = {
+            rustTarget = "aarch64-unknown-linux-musl";
+            crossTarget = "aarch64-unknown-linux-musl";
+          };
+          "i686-linux" = {
+            rustTarget = "i686-unknown-linux-musl";
+            crossTarget = "i686-unknown-linux-musl";
+          };
+
+          "x86_64-darwin" = {
+            rustTarget = "x86_64-apple-darwin";
+            crossTarget = "x86_64-darwin";
+          };
+          "aarch64-darwin" = {
+            rustTarget = "aarch64-apple-darwin";
+            crossTarget = "aarch64-darwin";
+          };
+        };
         cargoLock = {
           lockFile = ./Cargo.lock;
           outputHashes = {
@@ -141,8 +204,10 @@
             LD = "${winCC}/bin/${winCC.targetPrefix}cc";
           };
 
-        mkCrossRustPackage = rustTarget: crossTarget: packageName:
+        mkCrossRustPackage = arch: packageName:
           let
+            rustTarget = arch2targets."${arch}".rustTarget;
+            crossTarget = arch2targets."${arch}".crossTarget;
             pkgsCross = import nixpkgs {
               system = system;
               crossSystem.config = crossTarget;
@@ -164,7 +229,7 @@
             cargoBuildOptions = x: x ++ [ "--package" packageName ];
             version = manifest.version;
             strictDeps = true;
-            src = pkgs.lib.cleanSource ./.;
+            src = rustSrc;
             nativeBuildInputs = [
               pkgs.perl # Needed to build vendored OpenSSL.
             ];
@@ -182,16 +247,20 @@
             LD = "${pkgsCross.stdenv.cc}/bin/${pkgsCross.stdenv.cc.targetPrefix}cc";
           };
 
-        mk-aarch64-RustPackage = mkCrossRustPackage "aarch64-unknown-linux-musl" "aarch64-unknown-linux-musl";
+        mkRustPackages = arch: {
-        mk-i686-RustPackage = mkCrossRustPackage "i686-unknown-linux-musl" "i686-unknown-linux-musl";
+          "deltachat-repl-${arch}" = mkCrossRustPackage arch "deltachat-repl";
-        mk-x86_64-RustPackage = mkCrossRustPackage "x86_64-unknown-linux-musl" "x86_64-unknown-linux-musl";
+          "deltachat-rpc-server-${arch}" = mkCrossRustPackage arch "deltachat-rpc-server";
-        mk-armv7l-RustPackage = mkCrossRustPackage "armv7-unknown-linux-musleabihf" "armv7l-unknown-linux-musleabihf";
+        };
-        mk-armv6l-RustPackage = mkCrossRustPackage "arm-unknown-linux-musleabihf" "armv6l-unknown-linux-musleabihf";
       in
       {
         formatter = pkgs.nixpkgs-fmt;
 
-        packages = rec {
+        packages =
+          mkRustPackages "aarch64-linux" //
+          mkRustPackages "i686-linux" //
+          mkRustPackages "x86_64-linux" //
+          mkRustPackages "armv7l-linux" //
+          mkRustPackages "armv6l-linux" // rec {
             # Run with `nix run .#deltachat-repl foo.db`.
             deltachat-repl = mkRustPackage "deltachat-repl";
             deltachat-rpc-server = mkRustPackage "deltachat-rpc-server";
@@ -202,20 +271,7 @@
             deltachat-repl-win32 = mkWin32RustPackage "deltachat-repl";
             deltachat-rpc-server-win32 = mkWin32RustPackage "deltachat-rpc-server";
 
-          deltachat-repl-aarch64-linux = mk-aarch64-RustPackage "deltachat-repl";
-          deltachat-rpc-server-aarch64-linux = mk-aarch64-RustPackage "deltachat-rpc-server";
 
-          deltachat-repl-i686-linux = mk-i686-RustPackage "deltachat-repl";
-          deltachat-rpc-server-i686-linux = mk-i686-RustPackage "deltachat-rpc-server";
-
-          deltachat-repl-x86_64-linux = mk-x86_64-RustPackage "deltachat-repl";
-          deltachat-rpc-server-x86_64-linux = mk-x86_64-RustPackage "deltachat-rpc-server";
-
-          deltachat-repl-armv7l-linux = mk-armv7l-RustPackage "deltachat-repl";
-          deltachat-rpc-server-armv7l-linux = mk-armv7l-RustPackage "deltachat-rpc-server";
-
-          deltachat-repl-armv6l-linux = mk-armv6l-RustPackage "deltachat-repl";
-          deltachat-rpc-server-armv6l-linux = mk-armv6l-RustPackage "deltachat-rpc-server";
 
             # Run `nix build .#docs` to get C docs generated in `./result/`.
             docs =
@@ -232,35 +288,7 @@
               pkgs.stdenv.mkDerivation rec {
                 pname = "libdeltachat";
                 version = manifest.version;
-              src = nix-filter.lib {
+                src = rustSrc;
-                root = ./.;
-
-                # Include only necessary files
-                # to avoid rebuilds e.g. when README.md or flake.nix changes.
-                include = [
-                  ./benches
-                  ./assets
-                  ./Cargo.lock
-                  ./Cargo.toml
-                  ./CMakeLists.txt
-                  ./CONTRIBUTING.md
-                  ./deltachat_derive
-                  ./deltachat-ffi
-                  ./deltachat-jsonrpc
-                  ./deltachat-ratelimit
-                  ./deltachat-repl
-                  ./deltachat-rpc-client
-                  ./deltachat-time
-                  ./deltachat-rpc-server
-                  ./format-flowed
-                  ./release-date.in
-                  ./src
-                ];
-                exclude = [
-                  (nix-filter.lib.matchExt "nix")
-                  "flake.lock"
-                ];
-              };
                 cargoDeps = pkgs.rustPlatform.importCargoLock cargoLock;
 
                 nativeBuildInputs = [