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/libmesosphere/include/mesosphere/init/kern_init_layout.hpp

@@ -32,7 +32,7 @@ namespace ams::kern::init {
         u32 init_array_offset;
         u32 init_array_end_offset;
     };
-    static_assert(std::is_pod<KernelLayout>::value);
+    static_assert(util::is_pod<KernelLayout>::value);
     static_assert(sizeof(KernelLayout) == 0x30);
 
 }