Update diffstat to version 1.66 / rev 32 via SR 1146096
    
    https://build.opensuse.org/request/show/1146096
    by user pgajdos + anag+factory
    - update to 1.66:
      + improve handling of git diff's
      + update install-sh
      + improve configure script checks, reducing compiler warnings (forwarded request 1145993 from amanzini)