hake: add code for library dependencies
hake: add code for library dependencies

libDep is to be used inside hakefiles to delcare library dependencies.  For
example, libDep ["vfs"] is supposed to return all the libraries needed by the
VFS library.

8l/barrelfish,BarrelfishOS/barrelfish,8l/barrelfish,BarrelfishOS/barrelfish,BarrelfishOS/barrelfish,kishoredbn/barrelfish,linusyang/barrelfish,BarrelfishOS/barrelfish,mslovy/barrelfish,utsav2601/cmpe295A,mslovy/barrelfish,kishoredbn/barrelfish,mslovy/barrelfish,BarrelfishOS/barrelfish,8l/barrelfish,8l/barrelfish,kishoredbn/barrelfish,mslovy/barrelfish,utsav2601/cmpe295A,kishoredbn/barrelfish,linusyang/barrelfish,8l/barrelfish,utsav2601/cmpe295A,utsav2601/cmpe295A,8l/barrelfish,BarrelfishOS/barrelfish,mslovy/barrelfish,mslovy/barrelfish,linusyang/barrelfish,linusyang/barrelfish,kishoredbn/barrelfish,utsav2601/cmpe295A,kishoredbn/barrelfish,BarrelfishOS/barrelfish,BarrelfishOS/barrelfish,linusyang/barrelfish,BarrelfishOS/barrelfish,utsav2601/cmpe295A