> '>>' : Open the file with mode "a" (append) and write the second
> argument to the file, plus a newline. If no second argument is given,
> nothing is written (if the file didn't exist it will be created but
> empty; if the file did exist it will be unchanged).
Would it make sense to guarantee timestamp update even with an empty
second argument? Reasons in favor:
- Make is inherently timestamp based and clear rules are important. It
could create a new class of mysterious, hard-to-reproduce bugs if this
function sometimes updates the file and other times not.
- Something like $(info touch $@$(file >>$@)) could become an
efficient, portable, in-process pattern for "touching" a file.