Add the comment from Andrea Arcangeli about the correct

Add the comment from Andrea Arcangeli about the correct
place of setting the default childhandler within spawn().
Make sure that newline is printed out for last(1) even
if an utmp record entry is truncated.
Check if utmp not only exists but is writable and delay
writing out of the utmp runlevel record if utmp is not writable.
Be able to find libcrypt also on 64 bit based architectures.

git-svn-id: svn://svn.sv.gnu.org/sysvinit/sysvinit/trunk@27 456724a4-4300-0410-8514-c89748c515a2