add proxy (#2086)

packages/p/proxy/xmake.lua

@@ -0,0 +1,19 @@
+package("proxy")
+
+    set_kind("library", {headeronly = true})
+    set_homepage("https://github.com/microsoft/proxy")
+    set_description("Proxy: Easy Polymorphism in C++")
+    set_license("MIT")
+
+    add_urls("https://github.com/microsoft/proxy/archive/refs/tags/$(version).tar.gz",
+             "https://github.com/microsoft/proxy.git")
+
+    add_versions("1.1.1", "6852b135f0bb6de4dc723f76724794cff4e3d0d5706d09d0b2a4f749f309055d")
+
+    on_install(function (package)
+        os.cp("proxy.h", package:installdir("include"))
+    end)
+
+    on_test(function (package)
+        assert(package:has_cxxincludes("proxy.h", {configs = {languages = "c++20"}}))
+    end)