fix for math/octave on AMD64.

[Kay Lehmann]

Hello,

if you send-pr this, I think you need to mark octave-forge broken, since 
it needs octave with enable-shared.

Greets,
Kay

Roland Smith wrote:
> The attached patch allows octave to build on the amd64
> platform. Basically, on amd64 octave is compiled with --disable-shared.
> 
> Roland
> 
> 
> ------------------------------------------------------------------------