another 2.1.0 compile error

[A.L.M.Buxey at lboro.ac.uk]

Hi,
> Marinko Tarlac wrote:
> > 1.1.7 also requires ltdl
> 
>   The only changes made to 1.1.x from now on will be security related.
> 
>   i.e. no new features. no build fixes, etc.

I dont think it was a build fix request - more a comment
that 1.1.7 needs ltdl on some platforms due to the way
that chosen distro operates.  - its a helpful note to others
who get caught out by this error.

generally, its blindingly obvious when you see something like

Error - libfoo.h missing

you think, hmmm, i dont have an include. what package provides
that include?  

alan