`ndk-21-4-7075529` fails to build due to missing libpython2.7

[PapaTutuWawa]

It seems like ndk-21-4-7075529 (at least; I did not test any other NDK package) fails to build due
to a missing dependency of libpython2.7 during fixup. Overriding the package to also include python27 fixes this (for me).

Flake to reproduce

{
  description = "My Android project";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs";
    devshell.url = "github:numtide/devshell";
    flake-utils.url = "github:numtide/flake-utils";
    android.url = "github:tadfisher/android-nixpkgs";
  };

  outputs = { self, nixpkgs, devshell, flake-utils, android }:
    {
      overlay = final: prev: {
        inherit (self.packages.${final.system}) android-sdk android-studio;
      };
    }
    //
    flake-utils.lib.eachSystem [ "x86_64-linux" ] (system:
      let
        pkgs = import nixpkgs {
          inherit system;
          config = {
                allowUnfree = true;
        };

          overlays = [
            devshell.overlays.default
            self.overlay
          ];
        };
      in
      {
        packages = {
          android-sdk = android.sdk.${system} (sdkPkgs: with sdkPkgs; [
            # Useful packages for building and testing.
            build-tools-30-0-2
            cmdline-tools-latest
            emulator
            platform-tools
            platforms-android-30
            ndk-21-4-7075529
          ]);
        };
      }
    );
}

Build using nix build .#android-sdk.

The build failure

auto-patchelf: 7 dependencies could not be satisfied
error: auto-patchelf could not satisfy dependency libpython2.7.so.1.0 wanted by /nix/store/0si65fkwivqnhvqcf6d9zaq3b2brkzdg-ndk-21-4-7075529-21.4.7075529/toolchains/llvm/prebuilt/linux-x86_64/lib64/liblldb.so
error: auto-patchelf could not satisfy dependency libpython2.7.so.1.0 wanted by /nix/store/0si65fkwivqnhvqcf6d9zaq3b2brkzdg-ndk-21-4-7075529-21.4.7075529/toolchains/llvm/prebuilt/linux-x86_64/lib64/liblldb.so.9.0.9svn
error: auto-patchelf could not satisfy dependency libpython2.7.so.1.0 wanted by /nix/store/0si65fkwivqnhvqcf6d9zaq3b2brkzdg-ndk-21-4-7075529-21.4.7075529/toolchains/llvm/prebuilt/linux-x86_64/lib64/liblldb.so.9svn
warn: auto-patchelf ignoring missing liblog.so wanted by /nix/store/0si65fkwivqnhvqcf6d9zaq3b2brkzdg-ndk-21-4-7075529-21.4.7075529/toolchains/llvm/prebuilt/linux-x86_64/lib64/clang/9.0.9/lib/linux/libclang_rt.asan-x86_64-android.so
warn: auto-patchelf ignoring missing liblog.so wanted by /nix/store/0si65fkwivqnhvqcf6d9zaq3b2brkzdg-ndk-21-4-7075529-21.4.7075529/toolchains/llvm/prebuilt/linux-x86_64/lib64/clang/9.0.9/lib/linux/libclang_rt.scudo-x86_64-android.so
warn: auto-patchelf ignoring missing liblog.so wanted by /nix/store/0si65fkwivqnhvqcf6d9zaq3b2brkzdg-ndk-21-4-7075529-21.4.7075529/toolchains/llvm/prebuilt/linux-x86_64/lib64/clang/9.0.9/lib/linux/libclang_rt.scudo_minimal-x86_64-andro>
warn: auto-patchelf ignoring missing liblog.so wanted by /nix/store/0si65fkwivqnhvqcf6d9zaq3b2brkzdg-ndk-21-4-7075529-21.4.7075529/toolchains/llvm/prebuilt/linux-x86_64/lib64/clang/9.0.9/lib/linux/libclang_rt.ubsan_standalone-x86_64-an>
auto-patchelf failed to find all the required dependencies.
Add the missing dependencies to --libs or use `--ignore-missing="foo.so.1 bar.so etc.so"`.
/nix/store/fzb9wy1yz0hn69vxw12954szvrjnjjgk-stdenv-linux/setup: line 144: pop_var_context: head of shell_variables not a function context

I only included the end as that's the only occurence of the string error.

The workaround

As already mentioned, I was able to build the NDK package by just overriding it and including python27 in its build inputs.

{
  description = "My Android project";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs";
    devshell.url = "github:numtide/devshell";
    flake-utils.url = "github:numtide/flake-utils";
    android.url = "github:tadfisher/android-nixpkgs";
  };

  outputs = { self, nixpkgs, devshell, flake-utils, android }:
    {
      overlay = final: prev: {
        inherit (self.packages.${final.system}) android-sdk android-studio;
      };
    }
    //
    flake-utils.lib.eachSystem [ "x86_64-linux" ] (system:
      let
        pkgs = import nixpkgs {
          inherit system;
          config = {
                allowUnfree = true;
              permittedInsecurePackages = [
                "python-2.7.18.6"
              ];

        };

          overlays = [
            devshell.overlays.default
            self.overlay
          ];
        };
      in
      {
        packages = {
          android-sdk = android.sdk.${system} (sdkPkgs: with sdkPkgs; [
            # Useful packages for building and testing.
            build-tools-30-0-2
            cmdline-tools-latest
            emulator
            platform-tools
            platforms-android-30
            (ndk-21-4-7075529.overrideAttrs (old: {
                buildInputs = old.buildInputs ++ [ pkgs.python27 ];
            }))
          ]);
        };
      }
    );
}

EDIT: I tested this with all four available channels. On every channel, the build failed with the exact same error.

[tadfisher]

The issue is LLDB grew a Python dependency in NDK 21 only.