Remove some warnings from Config.cpp

- unused includes, and
- unused functions.

FEXCore/Source/Interface/Config/Config.cpp

@@ -19,12 +19,10 @@
 
 #include <array>
 #include <cstdlib>
-#include <functional>
 #include <optional>
 #include <stddef.h>
 #include <stdint.h>
 #include <string_view>
-#include <system_error>
 #include <type_traits>
 #include <utility>
 
@@ -113,14 +111,6 @@ fextl::string GetApplicationConfig(const std::string_view Program, bool Global)
   return fextl::fmt::format("{}{}.json", ConfigFile, Program);
 }
 
-void SetConfig(FEXCore::Context::Context* CTX, ConfigOption Option, uint64_t Config) {}
-
-void SetConfig(FEXCore::Context::Context* CTX, ConfigOption Option, const fextl::string& Config) {}
-
-uint64_t GetConfig(FEXCore::Context::Context* CTX, ConfigOption Option) {
-  return 0;
-}
-
 static fextl::map<FEXCore::Config::LayerType, fextl::unique_ptr<FEXCore::Config::Layer>> ConfigLayers;
 class MetaLayer;
 static FEXCore::Config::MetaLayer* Meta {};