[racket] pthreads, futures, and building racket 5.0.1 from source

At Wed, 1 Sep 2010 19:58:40 -0400, "David T. Pierson" wrote:
> This concerned me because the src/README contains a warning about
> pthreads:
> 
> > Unfortunately, Racket's normal stack handling and use of signals (for
> > its own thread scheduling) do not interact well with pthreads.  Thus,
> > when pthreads are enabled, Racket and GRacket cannot use interupt
> > timers, and the stack is limited to 1MB.  These restrictions can degrade
> > performance and thread-responsiveness.

That note is out-of-date. The stack-limit note is still true, but
specific to FreeBSD, and 1MB of stack space is usually plenty. It's
true that interrupt timers interact badly with pthreads, but they're
also not needed with pthreads, since a thread is created to play the
timer's role; there's no effect on thread-responsiveness.

You shouldn't worry about having futures enabled, and I'll fix the
note.