1. `make tools` will not updated `clog` when `clog/main.go` was changed,
except `${GOBIN}/clog` or `tools-stamp` was deleted. `gosum` has the
same problem.
2. $(GOBIN)/gosum was just like magic number.
1. `make tools` will not updated `clog` when `clog/main.go` was changed,
except `${GOBIN}/clog` or `tools-stamp` was deleted. `gosum` has the
same problem.
2. $(GOBIN)/gosum was just like magic number.