configure.ac: Add an --enable-all-modules option

This option will turn on or off all modules and most features when
enabled, unless a feature was explicitly changed from being
auto-detected. Currently, this means that pacct must be explicitly
enabled, since it defaults to "no" (while all others default to "auto").

This also means that Sun Streams are turned on even on Linux, which
leads to a compile error later. So on Linux, --enable-all-modules should
be used together with --disable-sun-streams.

Fixes #149.

Requested-by: Andras Mitzki <micek@balabit.hu>
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
afinet: max packet length for spoof source is set to 1024

If actual packet size is bigger than AFInetDestDriver.spoof_source_maxmsglen,
the packet is truncated.

AFInetDestDriver.spoof_source_maxmsglen is set to 1024
and cannot set via config file at this time.

Signed-off-by: Budai Laszlo <Laszlo.Budai@balabit.com>
afprog: kill program destination before stopping syslog-ng

Stop procedure of syslog-ng is not stopped program destination and it is
running after syslog-ng was stopped. This patch set program group ID to all
child processes of syslog-ng and kill them process that have the same
program gorup ID than syslog-ng before syslog-ng has been stoped.

Signed-off-by: Budai Laszlo <Laszlo.Budai@balabit.com>
nvtable: fix nvtable corruption in case an indirect value references itself

Whenever an indirect ref references itself, nvtable lookups become infinite
loops. Fix this by breaking the reference cycle in this case.

Signed-off-by: Balazs Scheidler <balazs.scheidler@balabit.com>
travis: run 'make distcheck' instead of 'make check'

Signed-off-by: Budai Laszlo <Laszlo.Budai@balabit.com>
Merge pull request #350 from lbudai/3.6/f/3.7-backports

3.6/f/3.7 backports
Preparations for syslog-ng 3.6.2

Bumped the version in VERSION, and added changes to NEWS.md.

Signed-off-by: Budai Laszlo <Laszlo.Budai@balabit.com>