Disable llvm in ppc64 (#1534071)
    
    From [1] "Disable llvm will use the internal bytecode interpreter rather than the llvm
      jit", so drop bytecode build condition and use condional on enable or disable
      llvm.
    
    [1] http://lists.clamav.net/pipermail/clamav-users/2017-May/004572.html