I noticed that to. For C++03 you might need it for scoped_ptr/shared_ptr, but not if you're going to require C++11. If you're going down the -lpthread route you should probably just use them rather than forcing the include on boost threads.

Im not coding much C++ lately, but i think if someone just pick some basic(base, ipc, net, etc..) parts of chromium and create a redistributable library with it.. it would be a very sane and powerful competitor to boost when you are coding in C++ 03..