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/fs/fs_file.hpp

@@ -34,7 +34,7 @@ namespace ams::fs {
         return !(lhs == rhs);
     }
 
-    static_assert(std::is_pod<ReadOption>::value && sizeof(ReadOption) == sizeof(u32));
+    static_assert(util::is_pod<ReadOption>::value && sizeof(ReadOption) == sizeof(u32));
 
     struct WriteOption {
         u32 value;
@@ -58,7 +58,7 @@ namespace ams::fs {
         return !(lhs == rhs);
     }
 
-    static_assert(std::is_pod<WriteOption>::value && sizeof(WriteOption) == sizeof(u32));
+    static_assert(util::is_pod<WriteOption>::value && sizeof(WriteOption) == sizeof(u32));
 
     struct FileHandle {
         void *handle;