# Declare a project id.
project make 
    # Specify requirements for this project. They will be propagated to child project.
    # Use 'bjam -n' to see that MACRO is defined when compiling lib/b.obj
    : requirements <define>MACRO 
    ; 

# Load a project located at "extlib", and associated with project-id "/extlib".
use-project /extlib : extlib ;

# Construct a target 'a' from a list of sources using the specified rule.
make a 
    :   a.o  # Use a target declared in this Jamfile
    lib/b.o  # Use a target from other Jamfile
    @/extlib/c.o  # Refer to a library by project-id

    : gcc.link ;


# Construct another target.
make a.o : a.cpp : gcc.compile ;