start adding crosstool-ng for ESP32 compiler

crosstool-ng--list-sources.patch

+diff --git a/scripts/functions b/scripts/functions
+index 17384476..168f8101 100644
+--- a/scripts/functions
++++ b/scripts/functions
+@@ -720,6 +720,12 @@ CT_DoGetFile()
+         T="${CT_CONNECT_TIMEOUT}"
+     fi
+ 
++    if [ "${CT_COLLECT_SOURCES_FOR_NIXOS}" = "y" ]; then
++        echo "DoGetFile: ${url} -> ${dest}" >>"$out"
++        touch "${dest}"
++        return 0
++    fi
++
+     CT_DoLog DEBUG "Trying '${url}'"
+     if [ "${CT_DOWNLOAD_AGENT_WGET}" = "y" ]; then
+         if CT_DoExecLog ALL wget ${CT_DOWNLOAD_WGET_OPTIONS} \
+@@ -782,6 +788,12 @@ CT_DoVerifyDigest()
+         CT_DoLog WARN "Not verifying '${file}': digest missing"
+         return 0
+     fi
++
++    if [ "${CT_COLLECT_SOURCES_FOR_NIXOS}" = "y" ]; then
++        echo "DoVerifyDigest: ${alg}, ${pkgdir}/chksum, ${file}" >>"$out"
++        return 0
++    fi
++
+     CT_DoLog EXTRA "Verifying ${alg^^} checksum for '${file}'"
+     chksum=`"${alg}sum" "${path}"`
+     chksum="${chksum%%[[:space:]]*}"
+@@ -846,6 +858,11 @@ CT_DoVerifySignature()
+     local sigfile
+     local cat
+ 
++    if [ "${CT_COLLECT_SOURCES_FOR_NIXOS}" = "y" ]; then
++        echo "DoVerifySignature: ${path}, ${url}, ${format}" >>"$out"
++        return 0
++    fi
++
+     CT_DoLog EXTRA "Verifying detached signature for '${file}'"
+     case "${method}" in
+     packed)
+@@ -1970,7 +1987,12 @@ CT_DoFetch()
+         # this would override empty (default) values with "default branch name" and
+         # "most current revision", respectively.
+ 
+-        CT_GetVersion_${devel_vcs}
++        if [ "${CT_COLLECT_SOURCES_FOR_NIXOS}" = "y" ]; then
++            echo "CT_GetVersion_${devel_vcs}: url=${devel_url}, branch=${devel_branch}, revision=${devel_revision}" >>"$out"
++            unique_id=fake
++        else
++            CT_GetVersion_${devel_vcs}
++        fi
+         if [ -z "${unique_id}" ]; then
+             CT_Abort "${pkg_name}: ${devel_vcs} did not set unique ID for branch/revision"
+         fi
+@@ -1994,7 +2016,11 @@ CT_DoFetch()
+         CT_DoLog EXTRA "Retrieving '${basename}' (${devel_vcs} ${devel_url} ${devel_branch} ${devel_revision})"
+         CT_MktempDir tmp_dir
+         CT_Pushd "${tmp_dir}"
+-        CT_Download_${devel_vcs}
++        if [ "${CT_COLLECT_SOURCES_FOR_NIXOS}" = "y" ]; then
++            echo "CT_Download_${devel_vcs}: ${devel_vcs} ${devel_url} ${devel_branch} ${devel_revision}" >>"$out"
++        else
++            CT_Download_${devel_vcs}
++        fi
+ 
+         # First setting above may not have determined the version (e.g. with Mercurial)
+         # Set the final, downloaded version.

default.nix

+# https://docs.espressif.com/projects/esp-idf/en/latest/esp32/get-started/linux-setup-scratch.html
+{ stdenv, fetchFromGitHub, ncurses, bison, flex, unzip, help2man, libtool, autoconf, automake, which, texinfo, file }:
+let
+  version = "2020r3";
+in stdenv.mkDerivation {
+  pname = "espressif-esp32-gcc";
+  inherit version;
+
+  srcs = [
+    (fetchFromGitHub {
+      owner = "espressif";
+      repo  = "crosstool-NG";
+      rev   = "esp-${version}";
+      sha256 = "sha256-KXibljETsZFCZOuwJPcEvWMBWZ11rYoGYlS7P5m8ojA=";
+    })
+    (fetchFromGitHub {
+      owner = "espressif";
+      repo  = "xtensa-overlays";
+      rev   = "4d8c98dcf2996ac55adba9f84fb00e1b9105ea54";
+      sha256 = "sha256-QKCB3yEkT1DBMBnK3lilJ0LacoqNMlgz8X+5XpEA6Zs=";
+    })
+  ];
+
+  buildInputs = [ ncurses ];
+  nativeBuildInputs = [ autoconf automake bison flex unzip help2man libtool which texinfo file ];
+
+  patches = [ ./crosstool-ng--list-sources.patch ];
+
+  convertScript = ./sources-to-nix-syntax.sh;
+
+  unpackPhase = ''
+    runHook preUnpack
+
+    srcs=($srcs)
+    cp -r ''${srcs[0]} source
+    cd source
+    chmod u+w .
+    rmdir overlays
+    cp -rT ''${srcs[1]} overlays
+    chmod -R u+w .
+
+    runHook postUnpack
+  '';
+
+  preConfigure = ''
+    bash ./bootstrap
+    configureFlags+=(--enable-local)
+  '';
+
+  compile = ''
+    make
+    ./ct-ng xtensa-esp32-elf
+    ( unset CC CXX; CT_COLLECT_SOURCES_FOR_NIXOS=y out=$PWD/sources ./ct-ng source )
+    $convertScript sources >$out
+  '';
+
+  installPhase = "";
+  #FIXME
+}

release.nix

+{ system ? builtins.currentSystem, pkgs ? import <nixpkgs> { inherit system; } }:
+pkgs.callPackage ./default.nix { }

sources-to-nix-syntax.sh

+#!/usr/bin/env bash
+
+cat $1
+echo TODO