add tl_optional (#3177)

packages/t/tl_optional/xmake.lua

@@ -0,0 +1,24 @@
+package("tl_optional")
+
+    set_kind("library", {headeronly = true})
+    set_homepage("https://github.com/TartanLlama/optional")
+    set_description("C++11/14/17 std::optional with functional-style extensions and support for references.")
+    set_license("CC0")
+
+    set_urls("https://github.com/TartanLlama/optional/archive/refs/tags/$(version).zip",
+             "https://github.com/TartanLlama/optional.git")
+
+    add_versions("v1.1.0", "a336bb10f51945369c1dd6dc6d2a7086602ab9cab52c98a7a6224bfd782bc0c7")
+
+    on_install(function (package)
+        os.cp("include/tl", package:installdir("include"))
+    end)
+
+    on_test(function (package)
+        assert(package:check_cxxsnippets({test = [[
+            void test() {
+                tl::optional<int> e1 = 42;
+            }
+        ]]}, {configs = {languages = "c++11"}, includes = {"tl/optional.hpp"}}))
+    end)
+