In @ChrisRackauckas 's blog, in “gotcha 7” a script is referenced (build_sysimg.jl, in JULIA_HOME/share/julia) … that I don’t have in my installation (obtained by git clone). The purpose of the script was to generate a custom system image, with all of the optimizations for my own machine, rather than the one supplied by the download. Is that script gone because it has been superseded by PackageCompiler.jl?
Edit: forgot hyperlink.