For performance reasons `stdout` is not unbuffered by default. That leads
to problems if after printing to `stdout` a read on `stdin` is performed.
For that reason interactive commands like `git clean -i` do not function
properly anymore if the `stdout` is not flushed by `fflush(stdout)` before
trying to read from `stdin`.
In the case of `git clean -i` all reads on `stdin` were preceded by a
`fflush(stdout)` call.
Signed-off-by: nalla <nalla@hamal.uberspace.de>
d13135a982