Otherwise a coredump started at the inconvinient moment can stop
shutdown.target leaving the system in a halfway-down state:
Pulling in shutdown.target/start from systemd-poweroff.service/start
Added job shutdown.target/start to transaction.
...
Keeping job shutdown.target/start because of systemd-poweroff.service/start
...
[ OK ] Stopped target Remote File Systems.
shutdown.target: starting held back, waiting for: systemd-networkd.socket
sysinit.target: stopping held back, waiting for: remount_tmp.service
systemd-coredump.socket: Incoming traffic
...
systemd-coredump@0-243-0.service: Trying to enqueue job systemd-coredump@0-243-0.service/start/replace
Added job systemd-coredump@0-243-0.service/start to transaction.
Pulling in systemd-journald.socket/start from systemd-coredump@0-243-0.service/start
Added job systemd-journald.socket/start to transaction.
Pulling in system.slice/start from systemd-journald.socket/start
Added job system.slice/start to transaction.
Pulling in -.slice/start from system.slice/start
Added job -.slice/start to transaction.
Pulling in system-systemd\x2dcoredump.slice/start from systemd-coredump@0-243-0.service/start
Added job system-systemd\x2dcoredump.slice/start to transaction.
Pulling in system.slice/start from system-systemd\x2dcoredump.slice/start
Pulling in shutdown.target/stop from system-systemd\x2dcoredump.slice/start
Added job shutdown.target/stop to transaction.
...
Keeping job systemd-poweroff.service/stop because of umount.target/stop
Keeping job shutdown.target/stop because of systemd-coredump@0-243-0.service/start
Fixes second systemd compilation problem against Linux 3.12 uapi
headers.
IFA_F_NOPREFIXROUTE is a usual #define appeared in Linux 3.14, so
AC_CHECK_DECLS is not necessary.
Entropy Graph code doesn't handle the error condition if open() of /proc entry
fails. Moreover, the file is only opened once and only first sample will contain
the correct value because the return value of pread() is also not handled
properly and file is not re-opened. Fix both problems.
Correctly handle the potential failure of fdopen() (because of OOM, for instance)
after potentially successful open(). Prevent leaking open fd in such case.