This was lost in #104893 when removing the warning ignores no longer relevant
when including the D3D12MemAlloc _header_ as external.
But we still compile the .cpp directly and it has this warning.
Clarified why have a wrapper for this file.
Credit and thanks to @bruzvg for multiple build fixes, update of 3rd-party items and MinGW support.
Co-authored-by: bruvzg <7645683+bruvzg@users.noreply.github.com>