I run:
./bootstrap.sh --prefix=./install --with-libraries=system,filesystem,program_options
and then:
./b2 install

I get the following under ./install/include/boost:
config
detail
filesystem
program_options
system
cerrno.hpp
config.hpp
cstdint.hpp
limits.hpp
version.hpp

Under the top directories there I get all the sub-headers for each library. But I don't get the main ones (the ones you actually include in a dependent program):
system.hpp
filesystem.hpp
program_options.hpp

What am I doing wrong here?