freeorion: fix build

`boost::system::posix_error` is deprecated since v1.37, however the
default Boost version in NixOS is 1.66.

The following upstream patch fixed the issue:
https://github.com/freeorion/freeorion/commit/c9b5b13fb81b1ed142dee0e843101c6b8832ca95

See ticket #36453