implement hid_get_input_report for Linux hidraw backend

Fixes #259

linux/hid.c

@@ -1065,13 +1065,25 @@ int HID_API_EXPORT hid_get_feature_report(hid_device *dev, unsigned char *data,
 	return res;
 }
 
-// Not supported by Linux HidRaw yet
 int HID_API_EXPORT HID_API_CALL hid_get_input_report(hid_device *dev, unsigned char *data, size_t length)
 {
+// HIDIOCGINPUT was added in Linux 5.11:
+// https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f43d3870cafa2a0f3854c1819c8385733db8f9ae
+// With older kernels, just return an error.
+#ifdef HIDIOCGINPUT
+	int res;
+
+	res = ioctl(dev->device_handle, HIDIOCGINPUT(length), data);
+	if (res < 0)
+		register_device_error_format(dev, "ioctl (GINPUT): %s", strerror(errno));
+
+	return res;
+#else
 	(void)dev;
 	(void)data;
 	(void)length;
 	return -1;
+#endif
 }
 
 void HID_API_EXPORT hid_close(hid_device *dev)