On Windows, libuv's one-time initialization changes the C runtime
library's  `_fmode` setting to `_O_BINARY`, thus causing files to open
as binary after that instead of the default `_O_TEXT` mode.  See
upstream libuv issue 840.  Work around the problem by performing libuv
initialization early and then restoring `_fmode`.

In particular, this currently affects server mode.  Without this fix,
the `_fmode` setting changes when the server mode initializes libuv.

Fixes: #16962