Add a nix flake with a shell

flake.nix

@@ -0,0 +1,62 @@
+{
+    description = "Osiris devshell flake";
+
+    inputs = {
+        nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+        rust-overlay.url = "github:oxalica/rust-overlay";
+        flake-utils.url = "github:numtide/flake-utils";
+    };
+
+    outputs =
+        {
+            self,
+            nixpkgs,
+            rust-overlay,
+            flake-utils,
+            ...
+        }:
+        flake-utils.lib.eachDefaultSystem (
+            system:
+            let
+                overlays = [ (import rust-overlay) ];
+                pkgs = import nixpkgs {
+                    inherit system overlays;
+                };
+            in
+            {
+                devShells.default = pkgs.mkShell {
+                    buildInputs = with pkgs; [
+                        just
+                        gcc-arm-embedded
+                        python313
+                        python313Packages.cmake
+                        python313Packages.pyelftools
+                        (rust-bin.stable.latest.default.override {
+                            extensions = [
+                                "cargo"
+                                "llvm-tools"
+                                "rust-analysis"
+                                "rust-analyzer"
+                                "rust-docs"
+                                "rustfmt"
+                            ];
+                            targets = [
+                                "thumbv7em-none-eabi"
+                            ];
+                        })
+                        cargo-binutils
+                        llvm
+                        clang
+                        glibc_multi
+                        ninja
+
+                        stlink
+                    ];
+
+                    shellHook = ''
+                        export LIBCLANG_PATH=${pkgs.llvmPackages.libclang.lib}/lib
+                    '';
+                };
+            }
+        );
+}