reallocarray(3) and its uses

[Pedro Giffuni]

Hello;

I wasn't a fan of bringing reallocarray(3) from OpenBSD, but since we 
have it, I thought I'd take a look at using it. It is rather easy to use 
so I went around opengrok'ing "realloc" in userland and crosschecking 
with OpenBSD and I got to this patch:

https://reviews.freebsd.org/D9915

Current reviewers are mute: I am unsure if they are just deeply 
impressed and don't want to speak up or if they are simply too busy 
(most likely the later). There are still more uses in some utilities but 
I wanted to see what people think of the general idea.

Pedro.