Each freshly allocated chunk must have both cinuse and pinuse set.
That is, each allocated chunk borders either a previously allocated
and still in-use chunk, or the base of its memory arena. This is
- ensured by making all allocations from the the `lowest' part of any
+ ensured by making all allocations from the `lowest' part of any
found chunk. Further, no free chunk physically borders another one,
so each free chunk is known to be preceded and followed by either
inuse chunks or the ends of memory.