function default_app_cpu_target()
    Sys.ARCH === :i686        ?  "pentium4;sandybridge,-xsaveopt,clone_all"                        :
    Sys.ARCH === :x86_64      ?  "generic;sandybridge,-xsaveopt,clone_all;haswell,-rdrnd,base(1)"  :
    Sys.ARCH === :arm         ?  "armv7-a;armv7-a,neon;armv7-a,neon,vfp4"                          :
    Sys.ARCH === :aarch64     ?  "generic"   #= is this really the best here? =#                   :
    Sys.ARCH === :powerpc64le ?  "pwr8"                                                            :
        "generic"
end