[Rivet] GSL headers in non-standard location

[Holger Schulz]

Frank Siegert wrote:
> Hi Holger,
>
> Holger Schulz, Thursday 23 July 2009:
>   
>> is it possible to tell the rivet installer where to find the gsl
>> headers?
>>     
>
> Do you mean your path to the GSL headers is different from what it picks 
> up automatically when you specify the --with-gsl=<DIR> switch?
>
> Frank
>   
Exactly, it appeared very strange to me, too.
I ran configure with

    --with-gsl=/opt/products/gsl/1.9

which contains the usual structure with "lib", "include" and so on.
In the mean time I have simply copied the include/gsl directory into 
Rivet/include
and everything is fine.

Holger