https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89864
--- Comment #15 from Jürgen Reuter <juergen.reuter at desy dot de> --- Sorry for the spam, now I got it, there was something old (i.e. new) lingering around still. Now, back to XCode 10.1 and command line tools from October 2018 with a different include/sys. Started compilation/bootstrapping of gcc again, hopefully it is working now.
