configure error after GCC update

[Olly Betts]

On Wed, Aug 10, 2016 at 04:53:22PM -0400, Ayush Tomar wrote:
> I updated GCC from 4.7 to 4.9. Since then configure is failing with this
> error:
> 
> checking if -lm is required for maths functions... configure: error: Failed
> to link a C++ program using <cmath>
> configure failed
> 
> Could someone tell what might be going wrong here and how to fix it?

I don't know of any issues with using GCC 4.9.

If you look at config.log in the directory where the failing configure
script is, it'll show you the test program it tries to compile and how
it fails (look at the *END* of the log and work back).

Cheers,
    Olly