Add linalg (#3202)

* Add linalg

* Remove comment; update sha256.

* Update xmake.lua

* Update xmake.lua

---------

Co-authored-by: ruki <[email protected]>

packages/l/linalg/xmake.lua

@@ -0,0 +1,24 @@
+package("linalg")
+    set_kind("library", {headeronly = true})
+    set_homepage("https://github.com/sgorsten/linalg")
+    set_description("linalg.h is a single header, public domain, short vector math library for C++.")
+    set_license("Unlicense license")
+
+    add_urls("https://github.com/sgorsten/linalg/archive/refs/tags/$(version).tar.gz",
+             "https://github.com/sgorsten/linalg.git")
+
+    add_versions("v2.2", "28640228988186EDAF7729177BFAB4C91170B303AD489407A4228CEB55A73EC2")
+
+    on_install("windows", "linux", "macosx", function (package)
+        os.cp("linalg.h", package:installdir("include"))
+    end)
+
+    on_test(function (package)
+        assert(package:check_cxxsnippets({test = [[
+        using namespace linalg::aliases;
+        float4 test(float3 a, float3 b, float3 c) {
+            float3 n = cross(b-a, c-a);
+            return {n, -dot(n,a)};
+        }
+    ]]}, {configs = {languages = "c++11"}, includes = "linalg.h"}))
+    end)