Add cxxopts third party dependency

.gitmodules

@@ -52,3 +52,6 @@
 [submodule "third_party/cpptoml"]
 	path = third_party/cpptoml
 	url = https://github.com/skystrife/cpptoml
+[submodule "third_party/cxxopts"]
+	path = third_party/cxxopts
+	url = https://github.com/jarro2783/cxxopts

premake5.lua

@@ -233,6 +233,7 @@ solution("xenia")
   include("third_party/aes_128.lua")
   include("third_party/capstone.lua")
   include("third_party/discord-rpc.lua")
+  include("third_party/cxxopts.lua")
   include("third_party/gflags.lua")
   include("third_party/cpptoml.lua")
   include("third_party/glew.lua")

third_party/cxxopts.lua

@@ -0,0 +1,9 @@
+group("third_party")
+project("cxxopts")
+  uuid("8b68cbe8-2da4-4f28-be14-9352eafa3168")
+  kind("Utility")
+  language("C++")
+  files({
+    "cxxopts/include/cxxopts.hpp",
+  })
+  warnings("Off")