1 make: "var-op-shell.mk" line 28: warning: "echo "failed"; false" returned non-zero status
2 make: "var-op-shell.mk" line 34: warning: "false" returned non-zero status
3 make: "var-op-shell.mk" line 59: warning: "kill -14 $$" exited on a signal
4 /bin/no/such/command: not found
5 make: "var-op-shell.mk" line 65: warning: "/bin/no/such/command" returned non-zero status