This patch provides an implementation of the '_nanosleep()' libc function,
which blocks on a timed semaphore for the given time, but at least 10ms.
This should result in better performance than creating a timer connection
on every call (for thread-safety), but could still be improved.
Fixes#158.
Removed dummy implementation of '_ioctl'. This function is called
internally within the libc, i.e., by 'tcgetattr'. For running
libreadline in Noux, we need to hook into those ioctl operations via
the libc plugin interface.
