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/source/capsrv/server/decodersrv/decodersrv_decoder_work_memory.hpp

@@ -23,6 +23,6 @@ namespace ams::capsrv::server {
     };
     static_assert(sizeof(DecoderWorkMemory)  == SoftwareJpegDecoderWorkMemorySize);
     static_assert(alignof(DecoderWorkMemory) == os::MemoryPageSize);
-    static_assert(std::is_pod<DecoderWorkMemory>::value);
+    static_assert(util::is_pod<DecoderWorkMemory>::value);
 
 }