unistd.h doesn't seem to be necessary but breaks the MS VC build.
unistd.h doesn't seem to be necessary but breaks the MS VC build.

bluerover/6lbr,MohamedSeliem/contiki,MohamedSeliem/contiki,bluerover/6lbr,bluerover/6lbr,arurke/contiki,MohamedSeliem/contiki,bluerover/6lbr,MohamedSeliem/contiki,MohamedSeliem/contiki,arurke/contiki,MohamedSeliem/contiki,MohamedSeliem/contiki,bluerover/6lbr,arurke/contiki,arurke/contiki,bluerover/6lbr,bluerover/6lbr,arurke/contiki,arurke/contiki,arurke/contiki