add lua syntax checker

syntax_checkers/lua.vim

@@ -0,0 +1,29 @@
+"============================================================================
+"File:        lua.vim
+"Description: Syntax checking plugin for syntastic.vim
+"Maintainer:  Gregor Uhlenheuer <kongo2002 at gmail dot com>
+"License:     This program is free software. It comes without any warranty,
+"             to the extent permitted by applicable law. You can redistribute
+"             it and/or modify it under the terms of the Do What The Fuck You
+"             Want To Public License, Version 2, as published by Sam Hocevar.
+"             See http://sam.zoy.org/wtfpl/COPYING for more details.
+"
+"============================================================================
+
+if exists('loaded_lua_syntax_checker')
+    finish
+endif
+let loaded_lua_syntax_checker = 1
+
+" check if the lua compiler is installed
+if !executable('luac')
+    finish
+endif
+
+function! SyntaxCheckers_lua_GetLocList()
+    let makeprg = 'luac -p ' . shellescape(expand('%'))
+    let errorformat =  'luac: %#%f:%l: %m'
+
+    return SyntasticMake({ 'makeprg': makeprg, 'errorformat': errorformat })
+endfunction
+