/usr/include/boost/iostreams/detail/config/ is in libboost1.46-dev 1.46.1-7ubuntu3.
This file is owned by root:root, with mode 0o755.
..
/usr/include/boost/iostreams/detail/config/auto_link.hpp
/usr/include/boost/iostreams/detail/config/bzip2.hpp
/usr/include/boost/iostreams/detail/config/codecvt.hpp
/usr/include/boost/iostreams/detail/config/disable_warnings.hpp
/usr/include/boost/iostreams/detail/config/dyn_link.hpp
/usr/include/boost/iostreams/detail/config/enable_warnings.hpp
/usr/include/boost/iostreams/detail/config/fpos.hpp
/usr/include/boost/iostreams/detail/config/gcc.hpp
/usr/include/boost/iostreams/detail/config/limits.hpp
/usr/include/boost/iostreams/detail/config/overload_resolution.hpp
/usr/include/boost/iostreams/detail/config/rtl.hpp
/usr/include/boost/iostreams/detail/config/unreachable_return.hpp
/usr/include/boost/iostreams/detail/config/wide_streams.hpp
/usr/include/boost/iostreams/detail/config/windows_posix.hpp
/usr/include/boost/iostreams/detail/config/zlib.hpp