https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63695
--- Comment #5 from Arnaud Charlet <charlet at gcc dot gnu.org> --- The addition of pragma No_Elaboration_Code_All in system.ads, which wasn't properly supported by your bootstrap compiler. In order to bootstrap with this change you either need an older compiler which doesn't know (and will ignore) about pragma No_Elaboration_Code_All, or knows about it and handles it properly (case for very recent compilers, but not yours). Note that strictly speaking you should always use a stable release as your bootstrap compiler, and not a snapshot, precisely to avoid this kind of subtle temporary issues (which are very rare, but may occur). Hope everything is now clear!
