add esp-idf tooling

xtensa-esp-elf.nix

@@ -0,0 +1,37 @@
+{
+  pkgs,
+  system,
+}: let
+  systems_table = {
+    "x86_64-linux" = {
+      system = "x86_64-linux-gnu";
+      hash = "sha256:1s86y3wss3vp5r6c076gz23hs62rkx1qc6vffjp42md86krrv1di";
+    };
+  };
+  system_download = systems_table.${system};
+in
+  pkgs.stdenv.mkDerivation rec {
+    pname = "xtensa-esp-elf";
+    version = "14.2.0_20241119";
+    src =
+      builtins.fetchurl
+      {
+        url = "https://github.com/espressif/crosstool-NG/releases/download/esp-${version}/${pname}-${version}-${system_download.system}.tar.gz";
+        sha256 = system_download.hash;
+      };
+
+    preferLocalBuild = true;
+
+    nativeBuildInputs = with pkgs; [
+      autoPatchelfHook
+    ];
+
+    buildInputs = with pkgs; [
+      pkgs.stdenv.cc.cc
+    ];
+
+    installPhase = ''
+      mkdir -p "$out"
+      cp -R ./{bin,lib} "$out"
+    '';
+  }