Messenger is slightly twisty when it comes to sending connection status
callbacks It will very likely need at the very least a partial refactor to
clean it up a bit. Toxcore shouldn't need void *userdata as deep as is
currently does.
(amend 1) Because of the nature of toxcore connection callbacks, I decided to
change this commit from statelessness for connections changes to statelessness
for friend requests. It's simpler this was and doesn't include doing anything
foolish in the time between commits.
group fixup because grayhatter doesn't want to do it
"arguably correct" is not how you write security sensitive code
Clear a compiler warning about types within a function.
The former is a non-standard glibc extension. On linux, it is implemented as a
call to sched_yield, so this change does nothing there. On OSX, pthread_yield
doesn't exist, and we already use sched_yield.
