From d652bd4455b8ede6371d4f56b3f718ef53c67963 Mon Sep 17 00:00:00 2001
From: Peter Barker <pbarker@barker.dropbear.id.au>
Date: Thu, 31 Oct 2019 16:25:09 +1100
Subject: [PATCH] Copter: correct compilation when optical flow is disabled

---
 ArduCopter/ekf_check.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/ArduCopter/ekf_check.cpp b/ArduCopter/ekf_check.cpp
index dcd2d1f2f8..8e1fdf701b 100644
--- a/ArduCopter/ekf_check.cpp
+++ b/ArduCopter/ekf_check.cpp
@@ -110,7 +110,11 @@ bool Copter::ekf_over_threshold()
     if (mag_variance.length() >= g.fs_ekf_thresh) {
         over_thresh_count++;
     }
-    if (!optflow.healthy() && (vel_variance >= (2.0f * g.fs_ekf_thresh))) {
+    bool optflow_healthy = false;
+#if OPTFLOW == ENABLED
+    optflow_healthy = optflow.healthy();
+#endif
+    if (!optflow_healthy && (vel_variance >= (2.0f * g.fs_ekf_thresh))) {
         over_thresh_count += 2;
     } else if (vel_variance >= g.fs_ekf_thresh) {
         over_thresh_count++;