Nice-to-have fix for autogen.sh

[Segher Boessenkool]

>>> Except for the fact that configure is really slow, I'd agree with  
>>> you.
>>
>> It doesn't take more than ten seconds on a really slow machine  
>> though,
>> so it is almost bearable...
>
> Actually, I'm well placed to know that configure is an order of  
> magnitude slower (I'm not kidding) if you're using MinGW or cygwin  
> on Windows.

On OSX it is ten times slower than on Linux already, but yes I remember
builds on cygwin being ten times slower than on Linux (on Linux it was
dominated by compiler time, on cygwin just by process startup).

I thought it would have improved a bit by now, and I thought mingw would
be better.  I also thought the generally much faster hardware we have
these days would have made it all sort-of a non-issue.  "Almost  
bearable".

> I could actually provide timings of the exact same machine (dual  
> core, 4 GB RAM) running the same libusb configure if you want to  
> see for yourselves.

Yeah I'd love to see some rough numbers.  autogen.sh (on a clean tree)
and configure separately, both cygwin and mingw?

> So I will agree with Vitali that configure can be and is really  
> slow on some platforms.

No one disagrees.  I wasn't aware of the _amount_ of pain you have to
live with though!


Segher