Add a workaround to a link error when using Boost < 1.57.
Add a workaround to a link error when using Boost < 1.57.

See the following links for more details:
* https://svn.boost.org/trac/boost/ticket/10038
* https://www.robertnitsch.de/notes/cpp/cpp11_boost_filesystem_undefined_reference_copy_file
* http://boost.2283326.n4.nabble.com/Filesystem-problems-with-g-std-c-0x-td2639716.html#a2639719

s3rvac/retdec-cpp