lib/lua: workaround builtins.match alias issue

It seems that `with lib` isn't (always) bringing `match` into scope
Odd, but we can fix by explicitly using `builtins.match`.

Author: MattSturgeon

lib/to-lua.nix

@@ -30,7 +30,7 @@ rec {
 
   # Valid lua identifiers are not reserved keywords, do not start with a digit,
   # and contain only letters, digits, and underscores.
-  isIdentifier = s: !(isKeyword s) && (match "[A-Za-z_][0-9A-Za-z_]*" s) == [ ];
+  isIdentifier = s: !(isKeyword s) && (builtins.match "[A-Za-z_][0-9A-Za-z_]*" s) == [ ];
 
   # toLua' with default options, aliased as toLuaObject at the top-level
   toLua = toLua' { };