luajit: add 2.0 version again

The reason will be apparent from the followup commit.
Also order the phases, quote shell variables, add myself to
maintainers, etc.

pkgs/development/interpreters/luajit/default.nix

@@ -1,20 +1,39 @@
 { stdenv, fetchurl }:
+rec {
 
-stdenv.mkDerivation rec {
+  luajit = luajit_2_1;
-  name    = "luajit-${version}";
+
+  luajit_2_0 = generic {
+    version = "2.0.5";
+    isStable = true;
+    sha256 = "0yg9q4q6v028bgh85317ykc9whgxgysp76qzaqgq55y6jy11yjw7";
+  };
+
+  luajit_2_1 = generic {
     version = "2.1.0-beta3";
-  luaversion = "5.1";
+    isStable = false;
-
-  src = fetchurl {
-    url    = "http://luajit.org/download/LuaJIT-${version}.tar.gz";
     sha256 = "1hyrhpkwjqsv54hnnx4cl8vk44h9d6c9w0fz1jfjz00w255y7lhs";
   };
 
-  enableParallelBuilding = true;
+
+  generic =
+    { version, sha256 ? null, isStable
+    , name ? "luajit-${version}"
+    , src ?
+      (fetchurl {
+        url = "http://luajit.org/download/LuaJIT-${version}.tar.gz";
+        inherit sha256;
+      })
+    }:
+
+    stdenv.mkDerivation rec {
+      inherit name version src;
+
+      luaversion = "5.1";
 
       patchPhase = ''
         substituteInPlace Makefile \
-      --replace /usr/local $out
+          --replace /usr/local "$out"
 
         substituteInPlace src/Makefile --replace gcc cc
       '' + stdenv.lib.optionalString (stdenv.cc.libc != null)
@@ -24,11 +43,17 @@ stdenv.mkDerivation rec {
       '';
 
       configurePhase = false;
+
       buildFlags = [ "amalg" ]; # Build highly optimized version
+      enableParallelBuilding = true;
+
       installPhase   = ''
-    make install INSTALL_INC=$out/include PREFIX=$out
+        make install INSTALL_INC="$out"/include PREFIX="$out"
-    ln -s $out/bin/luajit* $out/bin/lua
+        ln -s "$out"/bin/luajit-* "$out"/bin/lua
-    ln -s $out/bin/luajit* $out/bin/luajit
+      ''
+        + stdenv.lib.optionalString (!isStable)
+          ''
+            ln -s "$out"/bin/luajit-* "$out"/bin/luajit
           '';
 
       meta = with stdenv.lib; {
@@ -36,6 +61,7 @@ stdenv.mkDerivation rec {
         homepage    = http://luajit.org;
         license     = licenses.mit;
         platforms   = platforms.linux ++ platforms.darwin;
-    maintainers = with maintainers ; [ thoughtpolice smironov ];
+        maintainers = with maintainers ; [ thoughtpolice smironov vcunat ];
+      };
     };
 }

pkgs/top-level/all-packages.nix

@@ -6117,7 +6117,8 @@ with pkgs;
 
   luaPackages = lua52Packages;
 
-  luajit = callPackage ../development/interpreters/luajit {};
+  inherit (callPackages ../development/interpreters/luajit {})
+    luajit luajit_2_0 luajit_2_1;
 
   luarocks = luaPackages.luarocks;