[Bug ada/89349] segfault when building GCC 8 branch with GCC master

[ebotcazou at gcc dot gnu.org]

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  <charlet@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...