git-repo: update to 2.45, patch to run locally

The `repo` tool derivation by default includes only the main wrapper script
which fetches the actual tool sources from the internet. We modify the
derivation to provide default local sources patched with support for repo2nix,
unless specified otherwise with CLI parameters.

Flake compat was updated and nixpkgs-unstable re-introduced to facilitate this
change.

flake.nix

@@ -3,10 +3,14 @@
 
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-23.11";
+    nixpkgs-unstable.url = "github:NixOS/nixpkgs/nixos-unstable";
+
     androidPkgs.url = "github:tadfisher/android-nixpkgs/stable";
+
+    flake-compat.url = "github:nix-community/flake-compat";
   };
 
-  outputs = { self, nixpkgs, androidPkgs, ... }@inputs: let
+  outputs = { self, nixpkgs, nixpkgs-unstable, androidPkgs, flake-compat,  ... }@inputs: let
     pkgs = import ./pkgs/default.nix { inherit inputs; };
   in {
     # robotnixSystem evaluates a robotnix configuration
@@ -24,6 +28,7 @@
 
     packages.x86_64-linux = {
       manual = (import ./docs { inherit pkgs; }).manual;
+      gitRepo = pkgs.gitRepo;
     };
 
     devShell.x86_64-linux = pkgs.mkShell {

flake/compat.nix

@@ -0,0 +1,17 @@
+{ system ? builtins.currentSystem }:
+  let
+    lock               = builtins.fromJSON (builtins.readFile ./../flake.lock);
+    flake-compat-entry = lock.nodes.root.inputs.flake-compat;
+
+    inherit (lock.nodes."${ flake-compat-entry }".locked) owner repo narHash;
+
+    flake-compat = builtins.fetchTarball {
+                     url = "https://github.com/${ owner }/${ repo }/archive/${ lock.nodes.flake-compat.locked.rev }.tar.gz";
+                     sha256 = narHash;
+                   };
+  in
+    import flake-compat {
+      inherit system;
+
+       src =  ./..;
+    }

pkgs/default.nix

@@ -1,13 +1,7 @@
 # SPDX-FileCopyrightText: 2020 Daniel Fullmer and robotnix contributors
 # SPDX-License-Identifier: MIT
 
-{ inputs ? (import (
-    fetchTarball {
-      url = "https://github.com/edolstra/flake-compat/archive/12c64ca55c1014cdc1b16ed5a804aa8576601ff2.tar.gz";
-      sha256 = "0jm6nzb83wa6ai17ly9fzpqc40wg1viib8klq8lby54agpl213w5"; }
-  ) {
-    src =  ../.;
-  }).defaultNix.inputs,
+{ inputs ? (import ../flake/compat.nix).defaultNix.inputs,
   ... }@args:
 
 let
@@ -17,5 +11,5 @@ in nixpkgs.legacyPackages.x86_64-linux.appendOverlays [
     androidPkgs.packages = androidPkgs.packages.x86_64-linux;
     androidPkgs.sdk = androidPkgs.sdk.x86_64-linux;
   })
-  (import ./overlay.nix)
+  (import ./overlay.nix { inherit inputs; })
 ]