#1 add posix to the list of required dependencies on install

[Andrew Ulrich]

I keep getting an error in admin->media because I don't have php_posix installed because I'm using wampserver (windows apache mysql php stack). I'm also curious if there's a workaround for this, as I don't think wamp supports posix.

As it stands, I think it would be nice if support for posix were checked during install.