Compile fix for non-XKB builds

fcntl.h and unistd.h are required for non-XKB builds as well.

Change-Id: Ie3be5da919b37361ae2c235a308d4659cb455f80
Reviewed-by: Jan Arne Petersen <jan.petersen@kdab.com>
Reviewed-by: Jørgen Lind <jorgen.lind@digia.com>