New ld versions need an explicit link to boost.system (which was implicitly added before) because otherwise you get:
/usr/bin/ld: CMakeFiles/OgreXMLConverter.dir/src/main.cpp.o: undefined reference to symbol '_ZN5boost6system15system_categoryEv'
/usr/bin/ld: note: '_ZN5boost6system15system_categoryEv' is defined in DSO /lib64/libboost_system.so.1.50.0 so try adding it to the linker command line
/lib64/libboost_system.so.1.50.0: could not read symbols: Invalid operation
My fix is making this link explicit. There will be no odd effects as users of boost thread will have boost system anyway as it's actually a dependency.