Remove any old debug log:
rm ~/.bitcoin/debug.log
Build and start:
ninja
bitcoind -daemon
Gather results:
cat ~/.bitcoin/debug.log | grep -B5 "Early block [ar]" ; echo "Early blocks accepted: $(cat ~/.bitcoin/debug.log | grep "Early block accepted" | wc -l)" ; echo "Early blocks rejected: $(cat ~/.bitcoin/debug.log | grep "Early block rejected" | wc -l)" ; ./bitcoin-cli getchaintips
The getchaintips output at the end should indicate that you have not forked yourself off.