Fix check_jabber to work with Openfire servers

The plugin expected:

	<?xml version='1.0'?>

But Openfire sends:

	<?xml version='1.0' encoding='UTF-8'?>
check_file_age: Provide performance data
check_ifstatus: Fix "-n" and "-u" options

Ignore interface if it's specified via "-n" OR "-u", not just when it's
specified via "-n" AND "-u".
Fix perfdata to comply with perfdata UOM definition
check_apt: fix memset

Fix memset introduced by commit 9ce7369 ("plugins/check_apt.c - Print uninitialized ereg").

Signed-off-by: Sebastian Herbszt <herbszt@gmx.de>
check_ntp: fix null termination

Fix null termination introduced by commit a04df3e ("plugins/check_ntp.c - Verify struct from response").

Signed-off-by: Sebastian Herbszt <herbszt@gmx.de>
check_real: fix null termination

Fix null termination introduced by commit b61f51a ("plugins/check_real.c - recv string null terminate").

Signed-off-by: Sebastian Herbszt <herbszt@gmx.de>
check_snmp: Add thresholds to performance data
Introduce support for SNMPv3 context in check_snmp

snmpget already supports using SNMPv3 contexts using the option "-n".
Thus all we need to do is introduce a new argument to check_snmp and
pass the argument on to snmpget using snmpget's option "-n".
Since "-n" is already in use for check_snmp for a different purpose,
we use "-N" instead.
check_ssh: change warning to critical for protocal/version errors

It makes more sense to exit critical if a explicit version/protocol is requested. This
would also be more consistent with other plugins. Other string matching plugins like
check_snmp or check_http exit critical if the result does not match.

Signed-off-by: Sven Nierlein <sven@nierlein.de>

Closes #1268
avoid a segfault, if ulimit is set to unlimited
make constants from maxfd values (#1300)

its good practice to use constants instead of (random) values.

Signed-off-by: Sven Nierlein <sven@nierlein.de>
Added missing CR in DESCRIBE request.
Added particular ps command for HP-UX (check_procs)
Don't let check_disk hang on hanging file systems
check_disk: Fix pthread start routine type

The function pointer passed as third argument to pthread_create(3) must
be of type void *(*)(void *).
check_disk: Remove unused status variable

We didn't actually use the exit status provided by pthread_join(3) for
anything.
check_disk: Seperate declarations from code
update .gitignore

Add build-aux/test-driver to .gitignore.

Signed-off-by: Sebastian Herbszt <herbszt@gmx.de>
check_tcp: fix help description regarding escape option

The help description should print '\\' for backslash not just '\'.

Signed-off-by: Sebastian Herbszt <herbszt@gmx.de>