Add fast_float package (#1291)

* Add fast_float

* fast_float: Add header-only

* Fix include

* Test with C++11

packages/f/fast_float/xmake.lua

@@ -0,0 +1,23 @@
+package("fast_float")
+    set_kind("library", {headeronly = true})
+    set_homepage("https://github.com/fastfloat/fast_float")
+    set_description("Fast and exact implementation of the C++ from_chars functions for float and double types: 4x faster than strtod")
+    set_license("Apache-2.0")
+
+    add_urls("https://github.com/fastfloat/fast_float/archive/refs/tags/$(version).tar.gz",
+             "https://github.com/fastfloat/fast_float.git")
+    add_versions("v3.4.0", "a242877d2fae81ca412033f5ebf5dbc43cb029c56b4af78e33106b9a69f8f58e")
+
+    on_install(function (package)
+        os.vcp("include/fast_float", package:installdir("include"))
+    end)
+
+    on_test(function (package)
+        assert(package:check_cxxsnippets({test = [[
+            void test() {
+                const std::string input =  "3.1416 xyz ";
+                double result;
+                auto answer = fast_float::from_chars(input.data(), input.data()+input.size(), result);
+            }
+        ]]}, {configs = {languages = "c++11"}, includes = {"fast_float/fast_float.h"}}))
+    end)