Update Windows code to fix build breakage

MinGW has been updated: this causes problems due to changes in header
files, including COM stuff being pulled in resulting in 'interface' being
a reserved keyword, and changes to a few POSIX definitions.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
Implement writev on Windows

The network code depends on writev(), so implement it for Windows.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
server: ensure that fio_time_init() is called before option parsing

When run in server mode, jobs are processed before fio_time_init()
is called, which causes pthread_setspecific() to be called before
pthread_key_create(). Work around this by calling it in thread_main()
too.

Signed-off-by: Jens Axboe <axboe@kernel.dk>