[Cbc] muti-thread compile for cbc-2.7.8

[John Forrest]

Noli,

> So there is no proximity search algorithm in 2.7.8, why is it that it
> does not issued an error when I use the proximity switch (i.e.
> -proximity on) in 2.7.8?

This is a temporary quirk due to the complicated links in Cbc.  Both Cbc 
trunk and stable/2.7 use Clp/stable.  All parameters - both Cbc and Clp 
are set via a function in Clp.  So to get proximity search working in 
Cbc/trunk I had to add proximity switch to Clp/stable/ - so switch is 
accepted but the results are not interrogated by Cbc/stable.  2.8 will 
sort that out.

I could/should add some version testing in this function 
CbcOrClpParam.cpp?????
>
> Anybody manage to compile CBC trunk that does not segment fault when
> using proximity search?
>
I could make it segfault when going parallel.  I have put in a quick fix 
but will be looking at the way root heuristics are done when in parallel 
mode.  The problem was that somehow the heuristic thought a solution had 
been found BUT solution array had not been stored.

John