Refactor header include/unistd.h.
Refactor header include/unistd.h.

Sort the steady growing list of function declaration alphabetically, in order
to speed up human lookup algorithms.

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