Gotta handle old versions of Xcode that don’t know anything about that.

QGCCommon.pri

@@ -200,7 +200,9 @@ MacBuild | LinuxBuild {
         # Latest clang version has a buggy check for this which cause Qt headers to throw warnings on qmap.h
         QMAKE_CXXFLAGS_WARN_ON += -Wno-return-stack-address
         # Xcode 8.3 has issues on how MAVLink accesses (packed) message structure members.
-        QMAKE_CXXFLAGS_WARN_ON += -Wno-address-of-packed-member
+        # Note that this will fail when Xcode version reaches 10.x.x
+        XCODE_VERSION = $$system($$PWD/tools/get_xcode_version.sh)
+        greaterThan(XCODE_VERSION, 8.2.0): QMAKE_CXXFLAGS_WARN_ON += -Wno-address-of-packed-member
     }
 }
 

tools/get_xcode_version.sh

@@ -0,0 +1,3 @@
+#!/bin/bash
+xcodebuild -version 2>&1 | (head -n1) | awk  '{print $2}'
+