#1285 Added logging primitives to perl bindings

[Peter Valdemar Mørch]

This patch essentially introduces Perl bindings for snmplib/snmp_logging.c.

Because of that, it could be considered a fix for:

• #2327 SNMP::initMib(); SNMP::loadModules("ALL") prints to STDERR
• #2282 SNMP::Session->new(DestHost=>"bogus") prints to STDERR
• #2558 SNMP::Session->new( %badSNMPv3Options) prints to STDERR

It allows for:

my $log = SNMP::catch_log {
    $sess = SNMP::Session->new(DestHost => 'bogus');
};
printf "Logged error was: $log!\n";

Instead of the library printing to STDERR for us, we get this on STDOUT:

Logged error was: getaddrinfo: bogus Name or service not known!

(SNMP::catch_log is incidentally written in Perl using the new XS primitives _enable_log_callback and _disable_log_callback)

[Peter Valdemar Mørch]

Oh, no. How embarrassing. Last minute I introduced a debugging sub. My bad. Here is the correct patch: 0001-Added-logging-primitives-to-perl-bindings-REMOVED_DEBUG_SUB.patch