Hi,

> We decided to fix these by defining the macro BOOST_ERROR_CODE_HEADER_ONLY 
> according to this link: 
>
> http://www.boost.org/doc/libs/1_56_0/libs/system/doc/reference.html#Header-error_code 
> 
> However, when building Boost itself with this macro defined, we're 
> encountering several problems: 
> ...
> 2) We get multiple definitions of "boost::system::throws" 
> 

Defining the macro BOOST_SYSTEM_NO_DEPRECATED (see that doc page above)
resolved the issue of multiple definitions of "boost::system::throws".

Matthias