Vector improvements and their fallout
Fix p_realpath on OpenBSD

OpenBSD's realpath(3) doesn't require the last part of the path to
exist. Override p_realpath in this OS to bring it in line with the
library's assumptions.
Now with no multiply
Merge pull request #1285 from phkelley/vector

Vector improvements and their fallout
Merge pull request #1295 from carlosmn/obsd

Fix p_realpath on OpenBSD