* Fix cast[pointer] issues on nim-devel.
* More cast[T] fixes.
* Fix compilation error.
* Add oserrno.nim
Further fixes for Windows and Linux.
* MacOS fixes.
* More Windows fixes and attempt to fix 1.2, 1.4 branches.
* Implicitly import/export oserrno.
* Replace oserrno with osdefs.
* Return back oserrno.
* epoll to oserrno.
* datagram/stream to oserrno.
* common to oserrno.
* test to oserrno.
Eugene Kabanov