ports/119352: graphics/ilmbase configure tests for shared semaphores but uses non-shared sems

[Stephen Hurd]

John Baldwin wrote:
>> So, the patch is still needed, but not for much longer?
>>     
>
> Maybe the patch can be made conditional on the OS version?  I think we already 
> have that sort of behavior in other ports.
>   

It's always correct regardless of the OS version, it just makes no 
difference for OSs which support pshared.