Set format(printf) attribute to __KReturn2 function
Set format(printf) attribute to __KReturn2 function

This way, users of this function will get notified when they use options
(like invalid number of formatted variables).

kkaempf/konkretcmpi,kkaempf/konkretcmpi,rnovacek/konkretcmpi,rnovacek/konkretcmpi,kkaempf/konkretcmpi,rnovacek/konkretcmpi