> - it looks like cmake does not like building variant executables and object files, i.e. "with ROOT" and "without ROOT".
> 
> I need to set "-DHAVE_ROOT" for building "with ROOT" and unset it via remove_definitions() for building "without ROOT",
> but remove_definitions() and add_definitions() do not work on a per-target basis, instead they operate
> per-directory and per-project.

You should not use per-directory and per-project definitions, but per-target definitions, such as

target_compile_options(mhttpd PRIVATE -DMG_ENABLE_SSL)

> In midas, we build mlogger without ROOT (to avoid tangling it with the ROOT RPATH and ROOT shared libraries),
> but if ROOT is present, we build rmlogger "with ROOT support". Same for the analyzer (mana.o and rmana.o).
> 
> For now we have this:
> - mana.o is built with ROOT if ROOT is detected
> - rmana.o is not built
> - rmlogger is not built (not clear why)

I added rmlogger to the install instructions. I believe it was always built, but just not installed into the /bin directory.

Stefan