Number of contiguous elements to allocate.
Allocated memory block (null in case of OOM, overflow or zero-sized allocation).
XXX: It would have been nice to parameterize this by global structs following the same duck-typed interface of the core std.experimental allocators, but they don't seem to be linked in when compiling in betterC mode.
Allocates enough memory for a given number of elements of a certain type.
The allocated memory must be later deallocated if one wishes to avoid leaks. It will also be registered for GC scanning in case this is compiled in a GC-enabled mode (not betterC).