add boolean parameter use_system for searching boost

This boolean parameter is added to check_and_set_roots() and detect_lib_dirs()
when true it will first search the compiler library directories before checking
the standard lib directories. This is set to false when using BOOST_ROOT and
set to true when useing other system directories like /usr/local

Also simplify using a set to remove duplicate lib files

Also remove the part where you search the Cellar in homebrew, this is
unnescessary now that symlinks can be followed it should find boost
when searching /usr/local so no need to search the Cellar

0 files changed, 0 insertions, 0 deletions