add nlohmann_json

packages/n/nlohmann_json/xmake.lua

@@ -0,0 +1,12 @@
+package("nlohmann_json")
+
+    set_homepage("https://nlohmann.github.io/json/")
+    set_description("JSON for Modern C++")
+
+    add_urls("https://github.com/nlohmann/json/releases/download/$(version)/include.zip",
+             "https://github.com/nlohmann/json.git")
+    add_versions("v3.4.0", "bfec46fc0cee01c509cf064d2254517e7fa80d1e7647fea37cf81d97c5682bdc")
+
+    on_install(function (package)
+        os.cp("include", package:installdir())
+    end)