neovim: uses vimUtils to make it configurable like vim_configurable is

- vimAlias argument , when true, will create a @out/bin/vim symlink
- configure argument, which will configure neovim the same way as it does
  vim_configurable. eg.: ~/.nixpkgs/config.nix

    {

      packageOverrides = pkgs : with pkgs; rec {
        vimg = neovim.override {
          vimAlias = true;
          configure = {
            customRC = ''
              set spell
            '';
            vam.pluginDictionaries = [
              { names = [ "youcompleteme" "ctrlp"]; }
            ];
          };
        };
      };

     }

Enjoy!

pkgs/applications/editors/neovim/default.nix

@@ -1,9 +1,13 @@
-{ stdenv, fetchFromGitHub, cmake, gettext, glib, libmsgpack
+{ stdenv, fetchFromGitHub, cmake, gettext, glib, libmsgpack, libtermkey
-, libtermkey, libtool, libuv, lpeg, lua, luajit, luaMessagePack
+, libtool, libuv, lpeg, lua, luajit, luaMessagePack, luabitop, ncurses, perl
-, luabitop, ncurses, perl, pkgconfig, unibilium, makeWrapper
+, pkgconfig, unibilium, makeWrapper, vimUtils
+
 , withPython ? true, pythonPackages, extraPythonPackages ? []
 , withPython3 ? true, python3Packages, extraPython3Packages ? []
 , withJemalloc ? true, jemalloc
+
+, vimAlias ? false
+, configure ? null
 }:
 
 with stdenv.lib;
@@ -48,74 +52,89 @@ let
     ignoreCollisions = true;
   };
 
-in stdenv.mkDerivation rec {
+  neovim = stdenv.mkDerivation rec {
-  name = "neovim-${version}";
+    name = "neovim-${version}";
 
-  src = fetchFromGitHub {
+    src = fetchFromGitHub {
-    sha256 = "1lycql0lwi7ynrsaln4kxybwvxb9fvganiq3ba4pnpcfgl155k1j";
+      sha256 = "1lycql0lwi7ynrsaln4kxybwvxb9fvganiq3ba4pnpcfgl155k1j";
-    rev = "6270d431aaeed71e7a8782411f36409ab8e0ee35";
+      rev = "6270d431aaeed71e7a8782411f36409ab8e0ee35";
-    repo = "neovim";
+      repo = "neovim";
-    owner = "neovim";
+      owner = "neovim";
-  };
+    };
 
-  enableParallelBuilding = true;
+    enableParallelBuilding = true;
 
-  buildInputs = [
+    buildInputs = [
-    makeWrapper
+      makeWrapper
-    cmake
+      cmake
-    glib
+      glib
-    libtermkey
+      libtermkey
-    libuv
+      libuv
-    luajit
+      luajit
-    lua
+      lua
-    lpeg
+      lpeg
-    luaMessagePack
+      luaMessagePack
-    luabitop
+      luabitop
-    libmsgpack
+      libmsgpack
-    ncurses
+      ncurses
-    neovimLibvterm
+      neovimLibvterm
-    pkgconfig
+      pkgconfig
-    unibilium
+      unibilium
-  ] ++ optional withJemalloc jemalloc;
+    ] ++ optional withJemalloc jemalloc;
 
-  nativeBuildInputs = [
+    nativeBuildInputs = [
-    gettext
+      gettext
-  ];
+    ];
 
-  LUA_CPATH="${lpeg}/lib/lua/${lua.luaversion}/?.so;${luabitop}/lib/lua/5.2/?.so";
+    LUA_CPATH="${lpeg}/lib/lua/${lua.luaversion}/?.so;${luabitop}/lib/lua/5.2/?.so";
-  LUA_PATH="${luaMessagePack}/share/lua/5.1/?.lua";
+    LUA_PATH="${luaMessagePack}/share/lua/5.1/?.lua";
 
-  postInstall = optionalString withPython ''
+    postInstall = optionalString withPython ''
-    ln -s ${pythonEnv}/bin/python $out/bin/nvim-python
+      ln -s ${pythonEnv}/bin/python $out/bin/nvim-python
-  '' + optionalString withPython3 ''
+    '' + optionalString withPython3 ''
-    ln -s ${python3Env}/bin/python $out/bin/nvim-python3
+      ln -s ${python3Env}/bin/python $out/bin/nvim-python3
-  '' + optionalString (withPython || withPython3) ''
+    '' + optionalString (withPython || withPython3) ''
-      wrapProgram $out/bin/nvim --add-flags "${
+        wrapProgram $out/bin/nvim --add-flags "${
-        (optionalString withPython
+          (optionalString withPython
-          ''--cmd \"let g:python_host_prog='$out/bin/nvim-python'\" '') +
+            ''--cmd \"let g:python_host_prog='$out/bin/nvim-python'\" '') +
-        (optionalString withPython3
+          (optionalString withPython3
-          ''--cmd \"let g:python3_host_prog='$out/bin/nvim-python3'\"'')
+            ''--cmd \"let g:python3_host_prog='$out/bin/nvim-python3'\" '')
-      }"
+        }"
-  '';
-
-  meta = {
-    description = "Vim text editor fork focused on extensibility and agility";
-    longDescription = ''
-      Neovim is a project that seeks to aggressively refactor Vim in order to:
-      - Simplify maintenance and encourage contributions
-      - Split the work between multiple developers
-      - Enable the implementation of new/modern user interfaces without any
-        modifications to the core source
-      - Improve extensibility with a new plugin architecture
     '';
-    homepage    = http://www.neovim.io;
+
-    # "Contributions committed before b17d96 by authors who did not sign the
+    meta = {
-    # Contributor License Agreement (CLA) remain under the Vim license.
+      description = "Vim text editor fork focused on extensibility and agility";
-    # Contributions committed after b17d96 are licensed under Apache 2.0 unless
+      longDescription = ''
-    # those contributions were copied from Vim (identified in the commit logs
+        Neovim is a project that seeks to aggressively refactor Vim in order to:
-    # by the vim-patch token). See LICENSE for details."
+        - Simplify maintenance and encourage contributions
-    license = with licenses; [ asl20 vim ];
+        - Split the work between multiple developers
-    maintainers = with maintainers; [ manveru nckx ];
+        - Enable the implementation of new/modern user interfaces without any
-    platforms   = platforms.unix;
+          modifications to the core source
+        - Improve extensibility with a new plugin architecture
+      '';
+      homepage    = http://www.neovim.io;
+      # "Contributions committed before b17d96 by authors who did not sign the
+      # Contributor License Agreement (CLA) remain under the Vim license.
+      # Contributions committed after b17d96 are licensed under Apache 2.0 unless
+      # those contributions were copied from Vim (identified in the commit logs
+      # by the vim-patch token). See LICENSE for details."
+      license = with licenses; [ asl20 vim ];
+      maintainers = with maintainers; [ manveru nckx garbas ];
+      platforms   = platforms.unix;
+    };
   };
+
+in if (vimAlias == false && configure == null) then neovim else stdenv.mkDerivation rec {
+  name = "neovim-${version}-configured";
+  buildInputs = [ makeWrapper ];
+  buildCommand = ''
+    mkdir -p $out/bin
+    for item in ${neovim}/bin/*; do
+      ln -s $item $out/bin/
+    done
+  '' + optionalString vimAlias ''
+    ln -s $out/bin/nvim $out/bin/vim
+  '' + optionalString (configure != null) ''
+    wrapProgram $out/bin/nvim --add-flags "-u ${vimUtils.vimrcFile configure}"
+  '';
 }