Move transport declarations into transport.h.

There are a few cloexec issues in here as an added bonus.

Change-Id: I1699d719d733f47878bdba0454230cf5ab6a60b6
diff --git a/adb/usb_windows.c b/adb/usb_windows.c
index a2d7226..3c5533b 100644
--- a/adb/usb_windows.c
+++ b/adb/usb_windows.c
@@ -14,19 +14,20 @@
  * limitations under the License.
  */
 
-#include <winsock2.h>
-#include <windows.h>
-#include <winerror.h>
-#include <errno.h>
-#include <usb100.h>
+#include <winsock2.h>  // winsock.h *must* be included before windows.h.
 #include <adb_api.h>
+#include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <usb100.h>
+#include <windows.h>
+#include <winerror.h>
 
 #include "sysdeps.h"
 
 #define   TRACE_TAG  TRACE_USB
 #include "adb.h"
+#include "transport.h"
 
 /** Structure usb_handle describes our connection to the usb device via
   AdbWinApi.dll. This structure is returned from usb_open() routine and