Arbitrarily split up to make git bisect easier.
These unnecessary #include's were found by combining an automated tool (which
determined likely candidates) and some brain power (which decided whether
the #include is also semantically superfluous).
This enable using global raw pointers rather than Singleton objects,
which solves some problems because global Singleton object could
be deleted when destructors are run.
Problem:
- `(void)` simply casts the expression to void. This is understood to
indicate that it is ignored, but this is really a compiler trick to
get the compiler to not generate a warning.
Solution:
- Use the `[[maybe_unused]]` attribute to indicate the value is unused.
Note:
- Functions taking a `(void)` argument list have also been changed to
`()` because this is not needed and shows up in the same grep
command.
Problem:
- Several files have missing includes. This results in complaints from
`clang-tidy`.
- `#ifdef` is followed by `#elif <value>` which evaluates to `0`.
Solution:
- Add missing includes.
- Change to `#elif defined(<value>)`.
MemoryManager cannot use the Singleton class because
MemoryManager::initialize is called before the global constructors
are run. That caused the Singleton to be re-initialized, causing
it to create another MemoryManager instance.
Fixes#3226
