bug#122: 23.0.60; Slowdown in directory scanning over time.

[Stefan Monnier]

> I've just modified the current code to avoid calling
> Fget_buffer_create when we alreay have
> Vcode_conversion_reused_workbuf.  But, I think it doens't
> influence the efficiency that much because
> Fget_buffer_create doesn't create a new buffer if a buffer
> of the specified name already exists.

But the title-problem showed that having many buffers (like 200 or so)
can cause this buffer-name-lookup to take a long time.  The worst part
is that having 200 buffers is not particularly excessive: I regularly
have Emacs session with a hundred buffers or so.  So we should avoid
this lookup loop whenever necessary.


        Stefan