clay: add package (#6013)

packages/c/clay/xmake.lua

@@ -0,0 +1,18 @@
+package("clay")
+    set_kind("library", {headeronly = true})
+    set_homepage("https://nicbarker.com/clay")
+    set_description("High performance UI layout library in C.")
+    set_license("zlib")
+
+    add_urls("https://github.com/nicbarker/clay/archive/refs/tags/$(version).tar.gz",
+             "https://github.com/nicbarker/clay.git")
+
+    add_versions("v0.12", "b36f19352635edeb6d770fe77fab267982d9f206beb541849578de9f0aaff825")
+
+    on_install(function (package)
+        os.cp("clay.h", package:installdir("include"))
+    end)
+
+    on_test(function (package)
+        assert(package:has_cxxincludes("clay.h", {configs = {languages = "c++20"}}))
+    end)