[boost] boost 1.39 to 1.40 difference: missing toolset and threading tag from library filename?

Is there a difference in the naming conventions of the libboost_*.so files from boost 1.39 to boost 1.40.0? When I build the boost 1.39 libs they have filenames like... "libboost_thread-gcc44-mt-1_39.so" ..but when I build boost 1.40.0 all the libs filenames are like so... "libboost_thread.so" Did the library naming change in 1.40 or are their new compile options to enable the library naming feature? Build options: (both used on 1.39 & 1.40.0) ------------------------- ./bootstrap.sh --prefix=/usr --libdir=/usr/lib64 ./bjam threading=multi System ------------- Slamd64 12.1(x86_64) using gcc 4.4.2 Any help would be appticiated! Todd :-)