Use new INSTALL_SYMLINKS setting
    
    Replace NO_CROSS_DIRECTORY_HARDLINKS and NO_INSTALL_HARDLINKS with
    INSTALL_SYMLINKS.  The result is slightly improved; all symlinks will
    point directly to the target rather than via multiple levels of
    symlinks.
    
    The rationale was covered in slightly more detail in d56cfc6 ("Use
    symlinks instead of hardlinks for installed binaries", 2018-03-15).
    
    Adjust the dangling-relative-symlink filter in the rpmlint config for
    the new target of the git-difftool symlink.