cs_libguarded: add package (#2794)

* cs_libguarded: add package

* fix cmake install

packages/c/cs_libguarded/xmake.lua

@@ -0,0 +1,23 @@
+package("cs_libguarded")
+    set_kind("library", {headeronly = true})
+    set_homepage("https://www.copperspice.com/")
+    set_description("Header-only library for multithreaded programming")
+    set_license("BSD-2-Clause")
+
+    add_urls("https://github.com/copperspice/cs_libguarded.git")
+    add_versions("2023.08.02", "1940568f8f21c2ef3d57551682dfc038772df6f6")
+
+    add_deps("cmake")
+
+    on_install(function (package)
+        import("package.tools.cmake").install(package, {"-DCMAKE_INSTALL_INCLUDEDIR=include"})
+    end)
+
+    on_test(function (package)
+        assert(package:check_cxxsnippets({test = [[
+            #include <CsLibGuarded/cs_cow_guarded.h>
+            void test() {
+                libguarded::cow_guarded<int, std::timed_mutex> data(0);
+            }
+        ]]}, {configs = {languages = "c++17"}}))
+    end)