https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89349
--- Comment #12 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
It's a known historical quirk which has been fixed on the mainline:
2018-05-25 Arnaud Charlet <char...@adacore.com>
* osint.ads (Unknown_Attributes): No longer pretend this is a constant.
(No_File_Info_Cache): Initialize separately.
* osint.adb (No_File_Info_Cache): Update initializer.
In osint.ads there is:
Unknown_Attributes : constant File_Attributes := (others => 0);
-- Will be initialized properly at elaboration (for efficiency later on,
-- avoid function calls every time we want to reset the attributes).
which is both put into read-only memory and written to later...
