snmpd_extend should be installed in sbin

Rename snmpd_extends to snmpd_extend

reset SIGPIPE for extends

Make sure agentxsocket path isn't too long

Be more concise with group documentation

limit nsExtendCommand, and nsExtendInput to 255 characters. Fix previous botched commit

If kill by signal, to something similar to sh and use signum + 128 as exit code

Update lineindex on getnext request only if we're in normal range

If cmd increments, lineindex should reset.

Flush errstr buffer if it's full

Retry wait to make sure no children were missed

Don't use reserved keyword

Use correct config file in manpage

Put shell command building inside child process so it can't take down the server

Do a duplicate check for extends

Limit upper bound of cachetime

Include include

Connect to -s socket

Make sure errors are written to the stderr pipe, not stdout

Make sure a get-request doesn't increase indices

Handle IMSG_FAIL

Make sure output and error buffer are flushed

A cachetime of -1 is valid, but currently doesn't work. So always cache for up to 1 second by setting accepting at least 0

Ignore SIGPIPE for obvious reasons

Add missing NULL check