Standardize logging with bgpd OK claudio@

Use imsg_get_fd() As usual proc_forward_imsg() is never forwarding a file descriptor so just use -1 there. This should be replaced by imsg_forward(). All other changes are simple conversions. OK tb@

relayd(8): change agentx_getsock to return void Only has one return value and it's never checked. ok martijn@, tb@

Make "relayctl reload" when agentx enabling is toggled in relayd.conf work consistently. OK benno@

Add some additional INT32_MAX overflow checks. These are unlikely to hit, but better safe then sorry. OK tb@

Let relayd make use of libagentx. No functional change intended. OK tb@ Enthousiasm from Mischa Peters

Remove trailing spaces & tabs

Rewrite the agentx code of relayd. This new framework should allow us to add new objects easier if so desired and should handle a lot more corner-cases. This commit should also fix the following: - On most (all) tables it omits the *Entry elements, making it not map to OPENBSD-RELAYD-MIB.txt. - sstolen returns the size of the sockaddr_in{,6}, instead of the sin{,6}_addr resulting in garbage data to be put in the ip-field. - relaydSessionPortIn and relaydSessionPortOut are swapped - relaydSessions only uses relaydSessionIndex, while OPENBSD-RELAYD-MIB.txt says it should have 2 indices - miscellaneous minor things related to the AGENTX-protocol, like wonky index handeling and returning NOSUCHINSTANCE where NOSUCHOBJECT should be returned, etc. This commit does remove traps, but it's large enough as is and I intent on adding it soon(tm). It also deprecates the snmp keyword in favour of an agentx keyword. The snmp keyword is still available, but will be removed in the future. Tweaks and OK denis@ on the relayd parts Tweaks and OK claudio@ on the agentx parts "Get it in" deraadt@