[PATCH v2] hw/usb/host-libusb.c: fix build with kernel < 5.0

[Fabrice Fontaine]

USBDEVFS_GET_SPEED is used since version 5.2.0 and
https://gitlab.com/qemu-project/qemu/-/commit/202d69a715a4b1824dcd7ec1683d027ed2bae6d3
resulting in the following build failure with kernel < 5.0:

../hw/usb/host-libusb.c: In function 'usb_host_open':
../hw/usb/host-libusb.c:953:32: error: 'USBDEVFS_GET_SPEED' undeclared (first 
use in this function); did you mean 'USBDEVFS_GETDRIVER'?
         int rc = ioctl(hostfd, USBDEVFS_GET_SPEED, NULL);
                                ^~~~~~~~~~~~~~~~~~
                                USBDEVFS_GETDRIVER

A tentative was made to fix this build failure with
https://gitlab.com/qemu-project/qemu/-/commit/4969e697c15ac536d5c0700381d5d026ef7f0588

However, the assumption that distros with old kernels also have old
libusb is just wrong so also add a check for defined(USBDEVFS_GET_SPEED)

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
---
Changes v1 -> v2:
 - Fix error about line being over 90 characters

 hw/usb/host-libusb.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/hw/usb/host-libusb.c b/hw/usb/host-libusb.c
index b950501d10..07ccceb16d 100644
--- a/hw/usb/host-libusb.c
+++ b/hw/usb/host-libusb.c
@@ -941,7 +941,8 @@ static int usb_host_open(USBHostDevice *s, libusb_device 
*dev, int hostfd)
     usb_host_ep_update(s);
 
     libusb_speed = libusb_get_device_speed(dev);
-#if LIBUSB_API_VERSION >= 0x01000107 && defined(CONFIG_LINUX)
+#if LIBUSB_API_VERSION >= 0x01000107 && defined(CONFIG_LINUX) && \
+       defined(USBDEVFS_GET_SPEED)
     if (hostfd && libusb_speed == 0) {
         /*
          * Workaround libusb bug: libusb_get_device_speed() does not
-- 
2.29.2