diff --git a/unity.inc.php b/unity.inc.php
index 241519b..cd3133c 100644
--- a/unity.inc.php
+++ b/unity.inc.php
@@ -32,7 +32,6 @@ task('unity_kill', function()
   }
 });
 
-
 function unity_exec($func, $build_target = "", $quit = true, $batchmode = true)
 {
   global $GAME_ROOT;
@@ -159,3 +158,170 @@ function get_unity_dir()
     return "$app_dir/Unity.app/Contents/"; 
 }
 
+function mono_mcs_bin()
+{
+  if(!get("USE_UNITY_MONO"))
+    return 'mcs';
+
+  $unity_dir = get_unity_dir();
+
+  if(!is_dir($unity_dir))
+    throw new Exception("Unity directory doesn't exist: $unity_dir");
+
+  $canidates = array(
+    "$unity_dir/Mono/bin/gmcs",
+    "$unity_dir/MonoBleedingEdge/bin/mcs",
+    "$unity_dir/Frameworks/Mono/bin/gmcs",
+    "$unity_dir/Mono/bin/gmcs",
+  );
+
+  foreach($canidates as $mcs_bin)
+  {
+    if(is_file($mcs_bin))
+    {
+      if(is_win())
+        return '"' . normalize_path($mcs_bin, false) . '"';
+      else
+        return $mcs_bin;
+    }
+  }
+  
+  throw new Exception("Mono compiler binary not found");
+}
+
+function mono_try_override_path()
+{
+  if(!get("USE_UNITY_MONO"))
+    return '';
+  
+  $mono_dir = dirname(trim(mono_mcs_bin(), '"'));
+  $prev_path = getenv('PATH');
+  echo "UNITY MONO PATH=$mono_dir\n";
+  putenv("PATH=$mono_dir".(is_win() ? ";" : ":")."$prev_path");
+  return $prev_path;
+}
+
+function mono_try_restore_path($prev_path)
+{
+  if(!get("USE_UNITY_MONO"))
+    return;
+  
+  putenv("PATH=$prev_path");
+}
+
+function build_mono_dll($src_spec, $out_file, $ref_dlls = array(), $mcs_opts = "")
+{
+  build_mono($src_spec, $out_file, $ref_dlls, "$mcs_opts -target:library");
+}
+
+function build_mono($src_spec, $out_file, $ref_dlls = array(), $mcs_opts = "")
+{
+  global $GAME_ROOT;
+
+  $unity_dir = get_unity_dir();
+  $mcs_bin = mono_mcs_bin();
+
+  if(is_array($src_spec))
+    $sources = $src_spec;
+  else if(is_dir($src_spec))
+    $sources = scan_files_rec(array($src_spec), array('.cs'));
+  else
+    $sources = glob($src_spec);
+
+  $sources_str = '';
+  foreach($sources as $src)
+  {
+    if(is_win())
+      $sources_str .= '"'.normalize_path($src, !is_win()).'" ';
+    else
+      $sources_str .= '\''.normalize_path($src, !is_win()).'\' ';
+  }
+    
+  $deps = $sources;
+
+  $refs_str = "";
+  foreach($ref_dlls as $ref_dll)
+  {
+    if($ref_dll === "UnityEngine.dll")
+    {
+      $ref_dll = "$unity_dir/Managed/UnityEngine.dll"; 
+      if(!is_file($ref_dll))
+        $ref_dll = "$unity_dir/Frameworks/Managed/UnityEngine.dll";
+    }
+
+    $ref_dll = normalize_path($ref_dll, !is_win());
+    $refs_str .= "-r:\"$ref_dll\" ";
+    $deps[] = $ref_dll;
+  }
+
+  $out_file = normalize_path($out_file, !is_win());
+  $cmd = "$mcs_bin $mcs_opts $refs_str -out:$out_file $sources_str";
+  if(is_string($src_spec) && is_dir($src_spec))
+    $cmd = "cd $src_spec && $cmd";
+
+  $cmd_hash = crc32($cmd);
+  $cmd_hash_file = "$GAME_ROOT/build/" . crc32($out_file) . ".mhash";
+  if(!is_file($cmd_hash_file) || file_get_contents($cmd_hash_file) != "$cmd_hash")
+    file_put_contents($cmd_hash_file, "$cmd_hash");
+  $deps[] = $cmd_hash_file;
+
+  if(need_to_regen($out_file, $deps))
+  {
+    ensure_mkdir(dirname($out_file));
+    shell($cmd);
+    echo "> $out_file " . round(filesize($out_file)/1024, 2) . "kb\n";
+  }
+}
+
+function run_mono($exe_file)
+{
+  $app_dir = get('UNITY_APP_DIR');
+
+  if(is_win())
+  {
+    $unity_dir = "$app_dir/Editor/Data";
+    $mono_bin = '"' . normalize_path("$unity_dir/Mono/bin/mono", !is_win()) . '"';
+  }  
+  else
+  {
+    $unity_dir = "$app_dir/Unity.app/Contents/"; 
+    
+    if(is_dir("$unity_dir/Frameworks/Mono"))
+      $mono_bin = "$unity_dir/Frameworks/Mono/bin/mono";
+    else
+      $mono_bin = "$unity_dir/Mono/bin/mono";
+  }
+
+  $exe_file = normalize_path($exe_file, !is_win());
+  $mono_path = realpath(dirname($mono_bin) . '/../lib/mono/unity'); 
+  putenv("MONO_PATH=$mono_path"); //To LOCATION_PATH?
+  $cmd = "$mono_bin $exe_file";
+  shell($cmd);
+}
+
+function build_option_exists($option)
+{
+  return strpos(getor("BUILD_CLIENT_OPTS", ""), $option) !== FALSE;
+}
+
+function build_option_add($option)
+{
+  if(build_option_exists($option))
+    return;
+
+  $propname = "BUILD_CLIENT_OPTS";
+
+  $opts = getor($propname, "");
+  if(strlen($opts) > 0)
+    $opts .= ",$option";
+  else
+    $opts = $option;
+
+  set($propname, $opts);
+}
+
+function is_gradle_project_export() 
+{
+  return build_option_exists("AcceptExternalModificationsToPlayer");
+}
+