[WIP] C/C++ development environment

Package list may have redundancies or even inconsistencies, I don't
really know what I'm doing.

This does seem to work for code browsing (LSP support with ccls works
with doom emacs), and building / debugging a few projects I tried...

c-cpp/.envrc

@@ -0,0 +1 @@
+use flake .

c-cpp/flake.lock

@@ -0,0 +1,43 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "locked": {
+        "lastModified": 1678901627,
+        "narHash": "sha256-U02riOqrKKzwjsxc/400XnElV+UtPUQWpANPlyazjH0=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "93a2b84fc4b70d9e089d029deacc3583435c2ed6",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1679163677,
+        "narHash": "sha256-VC0tc3EjJZFPXgucFQAYMIHce5nJWYR0kVCk4TVg6gg=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "c3912035d00ef755ab19394488b41feab95d2e40",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "release-22.11",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

c-cpp/flake.nix

@@ -0,0 +1,54 @@
+{
+  description = "A Nix-flake-based C/C++ development environment";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/release-22.11";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs =
+    { self
+    , nixpkgs
+    , flake-utils
+    }:
+
+    flake-utils.lib.eachDefaultSystem (system:
+    let
+      pkgs = import nixpkgs { inherit system; };
+    in
+    {
+      devShells.default = pkgs.mkShell {
+        packages = with pkgs; [
+          # FIXME split into 3 different profiles?
+          stdenv
+          clangStdenv
+          gccStdenv
+
+          clang
+          llvmPackages_latest.bintools # lld https://matklad.github.io/2022/03/14/rpath-or-why-lld-doesnt-work-on-nixos.html
+
+          lldb
+          gdb
+
+          valgrind
+
+          # FIXME is this necessary? shouldn't be in stdenv?
+          binutils
+          coreutils
+          util-linux
+
+          pkg-config
+          libtool
+
+          automake autoconf
+          cmake cmake-language-server
+          ninja
+
+          unzip # needed for doom emacs gdb support
+
+          ccls
+          #sourcekit-lsp
+        ];
+      };
+    });
+}

flake.nix

@@ -10,6 +10,11 @@
   outputs = { self, flake-utils, nixpkgs }:
     {
       templates = rec {
+        c-cpp = {
+          path = ./c-cpp;
+          description = "C/CPP development environment based on nixpkg's stdenv";
+        };
+
         clojure = {
           path = ./clojure;
           description = "Clojure development environment";