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

Subject: [boost] boost 1.39 to 1.40 difference: missing toolset and threading tag from library filename?
From: Todd Lovette (captntoad_at_[hidden])
Date: 2009-10-25 00:40:43

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 :-)