sys/: Wait until the window is created before using it; guard unistd.h includes with...

sys/: Wait until the window is created before using it; guard unistd.h includes with HAVE_UNISTD_H. (#366523)

Original commit message from CVS:
Patch by: Sergey Scobich  <sergey dot scobich at gmail com>
* sys/directdraw/gstdirectdrawsink.c:
(gst_directdrawsink_window_thread),
(gst_directdrawsink_create_default_window):
* sys/directdraw/gstdirectdrawsink.h:
* sys/directsound/gstdirectsoundsink.c:
Wait until the window is created before using it; guard unistd.h
includes with HAVE_UNISTD_H. (#366523)
* win32/vs8/libgstdirectdraw.vcproj:
* win32/vs8/libgstdirectsound.vcproj:
Update project files.