Add nanobench (#1967)

* Add nanobench

* Update xmake.lua

* Set headeronly

packages/n/nanobench/xmake.lua

@@ -0,0 +1,28 @@
+package("nanobench")
+    set_kind("library", {headeronly = true})
+    set_homepage("https://nanobench.ankerl.com")
+    set_description("Simple, fast, accurate single-header microbenchmarking functionality for C++11/14/17/20")
+    set_license("MIT")
+
+    add_urls("https://github.com/martinus/nanobench/archive/refs/tags/$(version).tar.gz",
+             "https://github.com/martinus/nanobench.git")
+    add_versions("v4.3.11", "53a5a913fa695c23546661bf2cd22b299e10a3e994d9ed97daf89b5cada0da70")
+
+    on_install(function (package)
+        os.cp("src/include/nanobench.h", package:installdir("include"))
+    end)
+
+    on_test(function (package)
+        assert(package:check_cxxsnippets({test = [[
+            void test() {
+                double d = 1.0;
+                ankerl::nanobench::Bench().run("some double ops", [&] {
+                    d += 1.0 / d;
+                    if (d > 5.0) {
+                        d -= 5.0;
+                    }
+                    ankerl::nanobench::doNotOptimizeAway(d);
+                });
+            }
+        ]]}, {configs = {languages = "c++11"}, defines = "ANKERL_NANOBENCH_IMPLEMENT", includes = "nanobench.h"}))
+    end)