Not working (fails to link libnetwork despite trying to add it in
several places), and I got bored with their custom buildsystem. Feel
free to improve.
Fix boost to not try using XSI shared memory as we don't support that.
Fix VCMI to link to libnetwork where it uses it.
Now failing at install because there is no 'make install'. Will write a
manual copy of relevant files to the package later.