Fall back to readlink -f if realpath is not available or fails

wait-for-it.sh

@@ -142,7 +142,8 @@ CHILD=${CHILD:-0}
 QUIET=${QUIET:-0}
 
 # check to see if timeout is from busybox?
-TIMEOUT_PATH=$(realpath $(type -p timeout))
+TIMEOUT_PATH=$(type -p timeout)
+TIMEOUT_PATH=$(realpath $TIMEOUT_PATH 2>/dev/null || readlink -f $TIMEOUT_PATH)
 if [[ $TIMEOUT_PATH =~ "busybox" ]]; then
         ISBUSY=1
         BUSYTIMEFLAG="-t"