Fix build failure on Mac OS X 10.7

Apple documentation says kUSBDeviceSpeedSuper is available in 10.7 and
later but in fact it is only defined in the 10.8 SDK and later.

Closes #410
Closes #929

Signed-off-by: Nathan Hjelm <hjelmn@google.com>
diff --git a/libusb/os/darwin_usb.c b/libusb/os/darwin_usb.c
index 6de8102..bad0d8e 100644
--- a/libusb/os/darwin_usb.c
+++ b/libusb/os/darwin_usb.c
@@ -1146,7 +1146,7 @@
     case kUSBDeviceSpeedLow: dev->speed = LIBUSB_SPEED_LOW; break;
     case kUSBDeviceSpeedFull: dev->speed = LIBUSB_SPEED_FULL; break;
     case kUSBDeviceSpeedHigh: dev->speed = LIBUSB_SPEED_HIGH; break;
-#if MAC_OS_X_VERSION_MAX_ALLOWED >= 1070
+#if MAC_OS_X_VERSION_MAX_ALLOWED >= 1080
     case kUSBDeviceSpeedSuper: dev->speed = LIBUSB_SPEED_SUPER; break;
 #endif
 #if MAC_OS_X_VERSION_MAX_ALLOWED >= 101200
diff --git a/libusb/version_nano.h b/libusb/version_nano.h
index 1f2431b..20dc30c 100644
--- a/libusb/version_nano.h
+++ b/libusb/version_nano.h
@@ -1 +1 @@
-#define LIBUSB_NANO 11630
+#define LIBUSB_NANO 11631