Replace empty function parameter lists by a void list

In pure C, empty brackets in the function declaration doesn't mean no
parameters, but unspecified parameters. Make clear, we don't
accept any parameters.

I also accidentally removed trailing whitespaces. I am not sure whether this is desired, but 
I personally do not like spaces after the text. Hence my editor removes them by default.

Signed-off-by: Stefan Beller <stefanbeller@googlemail.com>