Switch atmosphere's build target to C++20. (#952)

* ams: update to build with gcc10/c++20

* remove mno-outline-atomics

* ams: take care of most TODO C++20s

* fusee/sept: update for gcc10

* whoosh, your code now uses pre-compiled headers

* make: dependency fixes

libraries/libstratosphere/include/stratosphere/mem/impl/mem_impl_common.hpp

@@ -65,6 +65,6 @@ namespace ams::mem::impl {
         size_t alloc_size;
         size_t hash;
     };
-    static_assert(std::is_pod<HeapHash>::value);
+    static_assert(util::is_pod<HeapHash>::value);
 
 }