Clarify M_MMAP_THRESHOLD

[Wolfram Gloger]

> We got a little bit confused on the purpose of M_MMAP_THRESHOLD and I
> think it should be explained better in the manual.

> --- manual/memory.texi	22 Jul 2002 00:57:09 -0000	1.76
> +++ manual/memory.texi	25 Feb 2003 05:26:43 -0000
> @@ -697,7 +697,8 @@ heap size such that excessive amounts of
>  All chunks larger than this value are allocated outside the normal
>  heap, using the @code{mmap} system call.  This way it is guaranteed
>  that the memory for these chunks can be returned to the system on
> -@code{free}.
> +@code{free}.  Note that requests smaller than this threshold might still
> +bet allocated via @code{mmap}.
   ^^^ be
>  @item M_MMAP_MAX
>  The maximum number of chunks to allocate with @code{mmap}.  Setting this
>  to zero disables all use of @code{mmap}.

Definitely ok with typo fix.

Regards,
Wolfram.