syslog-format: accept RFC5424 NILVALUE in timestamps

RFC5424 states:

In section 6:
TIMESTAMP       = NILVALUE / FULL-DATE "T" FULL-TIME

In section 6.2.3
   A syslog application MUST use the NILVALUE as TIMESTAMP if the syslog
   application is incapable of obtaining system time.

This patch changes syslog-ng to conform to this requirement as it reported
a parse error instead.

Reported-By: Vincent Brillault <spam@lerya.net>
Signed-off-by: Balazs Scheidler <bazsi@balabit.hu>
jsonparser: allow the use of generic parser related options

This opens the possibility to use the template() option to specify
the input for the parser.

Signed-off-by: Balazs Scheidler <bazsi@balabit.hu>
Wire in the SCL install/uninstall hooks

With the migration to a monolithic Makefile, the SCL install and
uninstall hooks were not running. This patch wires them back in.

Signed-off-by: Gergely Nagy <algernon@balabit.hu>
scl/Makefile.am: Make sure the installed SCLs are user-rwable

When installing the SCLs, make sure they're both readable and writable
by the installing user. This fixes the case of make distcheck combined
with make uninstall, which had these dirs set to read-list only.

Reported-by: Attila Szalay <sasa@balabit.hu>
Signed-off-by: Gergely Nagy <algernon@balabit.hu>
afamqp: Fix the build when AMQP is disabled

When building with --disable-amqp, don't include dummy.c in
BUILT_SOURCES, as that will lead to a build failure.

Reported-by: Tibor Benke <btibi@balabit.hu>
Signed-off-by: Gergely Nagy <algernon@balabit.hu>
Drop the top-level ChangeLog

Drop the generated ChangeLog, for the following reasons:

 * It's not useful, NEWS covers the user-visible changes in a much more
   digestible format, and the git log is available to everyone who wants
   or needs the more fine grained log.
 * The ChangeLog can only be regenerated from a git checkout, which
   makes it hard to remove it when doing distclean.
 * Not removing it at distclean time makes distcheck fail, and working
   around that is more work than the benefit of having ChangeLog at all.

Signed-off-by: Gergely Nagy <algernon@balabit.hu>