Improve Unicode support in FreeBSD

by Dmitry Selyutin for FreeBSD

Implement strcoll and strcoll_l functions, improve wc/mb functions as well as C11 and POSIX standart functions. One of the goals of this project is to let some projects like PostgreSQL to be built without ICU as dependency (thus strcoll and strcoll_l are the absolutely necessary functions). However, I personally treat this project as a possibility to provide better Unicode support everywhere where we can (I don't think we can do it till GSoC finishes, but at least we must take a good start).