[Ada] Speed up build of gnatools

[Robert Dewar]

On 9/6/2011 7:14 AM, Duncan Sands wrote:

> this means using as many processes as there are CPUs, right?  It
> seems pretty dubious to me to use more processes than the user maybe
> asked for.

We often find that the optimum number of processes is a little bit more
than the number of physical processes (not surprising when there is
mixed I/O computation going on.

> For example I have to restrict the number of CPUs used when building
> GCC to less than I have since otherwise my machine overheats and
> turns itself off.

That seems a (pretty disastrous) engineering error in the design of
your machine. In a properly designed machine, extra fans should come
on to counteract the extra heating (that's certainly what happens on
my Toshiba R700 with is the new core i7-2620M with four cores.

> Is there some way to get at the -j level the user passed to the
> top-level make and use that?

I am pretty sure you can specify any -j value you like, but will
let Arno clarify that.