unix, windows: map ERANGE errno
unix, windows: set required size on UV_ENOBUFS

When the supplied buffer is not big enough and UV_ENOBUFS is
returned, hint the user about the required size by setting
the len paramemeter to the required value.

Applies to:
- uv_pipe_getsockname
- uv_fs_event_getpath
- uv_fs_poll_getpath
unix, windows: clarify what uv_stream_set_blocking does

Also replace the assert with an error on unix.
windows: fix typo
makefile: fix build failure on MinGW