Add frozen (#1139)

* Add frozen

* frozen: fix download url

packages/f/frozen/xmake.lua

@@ -0,0 +1,26 @@
+package("frozen")
+
+    set_kind("library", {headeronly = true})
+    set_homepage("https://github.com/serge-sans-paille/frozen")
+    set_description("A header-only, constexpr alternative to gperf for C++14 users")
+    set_license("Apache-2.0")
+
+    set_urls("https://github.com/serge-sans-paille/frozen/archive/refs/tags/$(version).tar.gz",
+             "https://github.com/serge-sans-paille/frozen.git")
+
+    add_versions("1.1.1", "f7c7075750e8fceeac081e9ef01944f221b36d9725beac8681cbd2838d26be45")
+
+    on_install(function (package)
+        os.cp("include/frozen", package:installdir("include"))
+    end)
+
+    on_test(function (package)
+        assert(package:check_cxxsnippets({test = [[
+            constexpr frozen::set<int, 4> some_ints = {1,2,3,5};
+          
+            void test()
+            {
+                constexpr bool letitgo = some_ints.count(8);
+            }
+        ]]}, {configs = {languages = "c++14"}, includes = { "frozen/set.h"} }))
+    end)