windows: fix build

Make code compliant with C89 so it will compile.

References #609
Closes #611

Signed-off-by: Nathan Hjelm <hjelmn@google.com>

libusb/os/windows_winusb.c

diff --git a/libusb/os/windows_winusb.c b/libusb/os/windows_winusb.c
index efef3e6..1b42d4e 100644
--- a/libusb/os/windows_winusb.c
+++ b/libusb/os/windows_winusb.c
@@ -2421,12 +2421,12 @@
 */
 static int check_valid_interface(struct libusb_device_handle *dev_handle, unsigned short interface, int api_id)
 {
-	if (interface >= USB_MAXINTERFACES)
-		return -1;
-
 	struct winusb_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
 	struct winusb_device_priv *priv = _device_priv(dev_handle->dev);
 
+	if (interface >= USB_MAXINTERFACES)
+		return -1;
+
 	if ((api_id < USB_API_WINUSBX) || (api_id > USB_API_HID)) {
 		usbi_dbg("unsupported API ID");
 		return -1;

libusb/version_nano.h

diff --git a/libusb/version_nano.h b/libusb/version_nano.h
index f957476..fc95dc5 100644
--- a/libusb/version_nano.h
+++ b/libusb/version_nano.h
@@ -1 +1 @@
-#define LIBUSB_NANO 11392
+#define LIBUSB_NANO 11393