build(nix): add outputs for Android binaries

Using NDK 24 because NDK 23 does not have getauxval() function.

flake.lock

@@ -1,8 +1,50 @@
 {
   "nodes": {
+    "android": {
+      "inputs": {
+        "devshell": "devshell",
+        "flake-utils": "flake-utils_2",
+        "nixpkgs": "nixpkgs"
+      },
+      "locked": {
+        "lastModified": 1710633978,
+        "narHash": "sha256-yemnwSvW7cdWtXGpivFA5jDO35rGPs6fqxlQ4l6ODXs=",
+        "owner": "tadfisher",
+        "repo": "android-nixpkgs",
+        "rev": "e91fb3d8517538e5ad9b422c9a4f604b56008a9e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "tadfisher",
+        "repo": "android-nixpkgs",
+        "type": "github"
+      }
+    },
+    "devshell": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": [
+          "android",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1708939976,
+        "narHash": "sha256-O5+nFozxz2Vubpdl1YZtPrilcIXPcRAjqNdNE8oCRoA=",
+        "owner": "numtide",
+        "repo": "devshell",
+        "rev": "5ddecd67edbd568ebe0a55905273e56cc82aabe3",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "devshell",
+        "type": "github"
+      }
+    },
     "fenix": {
       "inputs": {
-        "nixpkgs": "nixpkgs",
+        "nixpkgs": "nixpkgs_2",
         "rust-analyzer-src": "rust-analyzer-src"
       },
       "locked": {
@@ -23,6 +65,42 @@
       "inputs": {
         "systems": "systems"
       },
+      "locked": {
+        "lastModified": 1701680307,
+        "narHash": "sha256-kAuep2h5ajznlPMD9rnQyffWG8EM/C73lejGofXvdM8=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "4022d587cbbfd70fe950c1e2083a02621806a725",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "flake-utils_2": {
+      "inputs": {
+        "systems": "systems_2"
+      },
+      "locked": {
+        "lastModified": 1709126324,
+        "narHash": "sha256-q6EQdSeUZOG26WelxqkmR7kArjgWCdw5sfJVHPH/7j8=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "d465f4819400de7c8d874d50b982301f28a84605",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "flake-utils_3": {
+      "inputs": {
+        "systems": "systems_3"
+      },
       "locked": {
         "lastModified": 1710146030,
         "narHash": "sha256-SZ5L6eA7HJ/nmkzGG7/ISclqe6oZdOZTNoesiInkXPQ=",
@@ -39,7 +117,7 @@
     },
     "naersk": {
       "inputs": {
-        "nixpkgs": "nixpkgs_2"
+        "nixpkgs": "nixpkgs_3"
       },
       "locked": {
         "lastModified": 1698420672,
@@ -71,6 +149,22 @@
       }
     },
     "nixpkgs": {
+      "locked": {
+        "lastModified": 1709237383,
+        "narHash": "sha256-cy6ArO4k5qTx+l5o+0mL9f5fa86tYUX3ozE1S+Txlds=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "1536926ef5621b09bba54035ae2bb6d806d72ac8",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs_2": {
       "locked": {
         "lastModified": 1710631334,
         "narHash": "sha256-rL5LSYd85kplL5othxK5lmAtjyMOBg390sGBTb3LRMM=",
@@ -86,7 +180,7 @@
         "type": "github"
       }
     },
-    "nixpkgs_2": {
+    "nixpkgs_3": {
       "locked": {
         "lastModified": 1710765496,
         "narHash": "sha256-p7ryWEeQfMwTB6E0wIUd5V2cFTgq+DRRBz2hYGnJZyA=",
@@ -100,7 +194,7 @@
         "type": "indirect"
       }
     },
-    "nixpkgs_3": {
+    "nixpkgs_4": {
       "locked": {
         "lastModified": 1710631334,
         "narHash": "sha256-rL5LSYd85kplL5othxK5lmAtjyMOBg390sGBTb3LRMM=",
@@ -118,11 +212,12 @@
     },
     "root": {
       "inputs": {
+        "android": "android",
         "fenix": "fenix",
-        "flake-utils": "flake-utils",
+        "flake-utils": "flake-utils_3",
         "naersk": "naersk",
         "nix-filter": "nix-filter",
-        "nixpkgs": "nixpkgs_3"
+        "nixpkgs": "nixpkgs_4"
       }
     },
     "rust-analyzer-src": {
@@ -156,6 +251,36 @@
         "repo": "default",
         "type": "github"
       }
+    },
+    "systems_2": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    },
+    "systems_3": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
     }
   },
   "root": "root",

flake.nix

@@ -6,8 +6,9 @@
     naersk.url = "github:nix-community/naersk";
     nix-filter.url = "github:numtide/nix-filter";
     nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+    android.url = "github:tadfisher/android-nixpkgs";
   };
-  outputs = { self, nixpkgs, flake-utils, nix-filter, naersk, fenix }:
+  outputs = { self, nixpkgs, flake-utils, nix-filter, naersk, fenix, android }:
     flake-utils.lib.eachDefaultSystem (system:
       let
         pkgs = nixpkgs.legacyPackages.${system};
@@ -15,6 +16,11 @@
         fenixPkgs = fenix.packages.${system};
         naersk' = pkgs.callPackage naersk { };
         manifest = (pkgs.lib.importTOML ./Cargo.toml).package;
+        androidSdk = android.sdk.${system} (sdkPkgs:
+          builtins.attrValues {
+            inherit (sdkPkgs) ndk-24-0-8215888 cmdline-tools-latest;
+          });
+        androidNdkRoot = "${androidSdk}/share/android-sdk/ndk/24.0.8215888";
 
         rustSrc = nix-filter.lib {
           root = ./.;
@@ -251,6 +257,71 @@
             LD = "${pkgsCross.stdenv.cc}/bin/${pkgsCross.stdenv.cc.targetPrefix}cc";
           };
 
+        androidAttrs = {
+          armeabi-v7a = {
+            cc = "armv7a-linux-androideabi19-clang";
+            rustTarget = "armv7-linux-androideabi";
+          };
+          arm64-v8a = {
+            cc = "aarch64-linux-android21-clang";
+            rustTarget = "aarch64-linux-android";
+          };
+          x86 = {
+            cc = "i686-linux-android19-clang";
+            rustTarget = "i686-linux-android";
+          };
+          x86_64 = {
+            cc = "x86_64-linux-android21-clang";
+            rustTarget = "x86_64-linux-android";
+          };
+        };
+
+        mkAndroidRustPackage = arch: packageName:
+          let
+            rustTarget = androidAttrs.${arch}.rustTarget;
+          in
+          let
+            toolchain = fenixPkgs.combine [
+              fenixPkgs.stable.rustc
+              fenixPkgs.stable.cargo
+              fenixPkgs.targets.${rustTarget}.stable.rust-std
+            ];
+            naersk-lib = pkgs.callPackage naersk {
+              cargo = toolchain;
+              rustc = toolchain;
+            };
+            targetToolchain = "${androidNdkRoot}/toolchains/llvm/prebuilt/linux-x86_64";
+            targetCcName = androidAttrs.${arch}.cc;
+            targetCc = "${targetToolchain}/bin/${targetCcName}";
+          in
+          naersk-lib.buildPackage rec {
+            pname = packageName;
+            cargoBuildOptions = x: x ++ [ "--package" packageName ];
+            version = manifest.version;
+            strictDeps = true;
+            src = rustSrc;
+            nativeBuildInputs = [
+              pkgs.perl # Needed to build vendored OpenSSL.
+            ];
+            auditable = false; # Avoid cargo-auditable failures.
+            doCheck = false; # Disable test as it requires network access.
+
+            CARGO_BUILD_TARGET = rustTarget;
+            TARGET_CC = "${targetCc}";
+            CARGO_BUILD_RUSTFLAGS = [
+              "-C"
+              "linker=${TARGET_CC}"
+            ];
+
+            CC = "${targetCc}";
+            LD = "${targetCc}";
+          };
+
+        mkAndroidPackages = arch: {
+          "deltachat-rpc-server-${arch}-android" = mkAndroidRustPackage arch "deltachat-rpc-server";
+          "deltachat-repl-${arch}-android" = mkAndroidRustPackage arch "deltachat-repl";
+        };
+
         mkRustPackages = arch:
           let
             rpc-server = mkCrossRustPackage arch "deltachat-rpc-server";
@@ -295,7 +366,11 @@
           mkRustPackages "i686-linux" //
           mkRustPackages "x86_64-linux" //
           mkRustPackages "armv7l-linux" //
-          mkRustPackages "armv6l-linux" // rec {
+          mkRustPackages "armv6l-linux" //
+          mkAndroidPackages "armeabi-v7a" //
+          mkAndroidPackages "arm64-v8a" //
+          mkAndroidPackages "x86" //
+          mkAndroidPackages "x86_64" // rec {
             # Run with `nix run .#deltachat-repl foo.db`.
             deltachat-repl = mkRustPackage "deltachat-repl";
             deltachat-rpc-server = mkRustPackage "deltachat-rpc-server";