Merge pull request #2622 from pqarmitage/updates

snap: attempt 5 to fix close_range() snap build with Linux 5.8

Author: pqarmitage

snap/snapcraft.yaml

@@ -257,7 +257,7 @@ parts:
       cat /usr/include/linux/version.h
       ls -lR /usr/include/linux
       rm -rf ${CRAFT_STAGE}/keepalived-linux-libc-dev
-      echo CFLAGS=$CFLAGS
+    echo CFLAGS=${CFLAGS:-}
       echo "Finding close_range.h"
       find /usr/include -name "close_range.h"
       cat /usr/include/linux/close_range.h || true