Re: [Ada] Remove useless pragma Warnings Off from runtime units

[Alexandre Oliva <oliva@gnu.org>]

Hello, Jan-Benedict,

On Jun 27, 2022, Jan-Benedict Glaw <jbglaw@lug-owl.de> wrote:

> For me, this patch broke building a basic cross compiler using Debian
> sid's "gcc-snapshot" package as the build/host compiler

Thanks for reporting the problem you've encountered, and for your
interest.

AFAIK the general recommendation for building GCC is to either bootstrap
it, using a native compiler that meets the build documented
requirements, or use the same precompiled version of the compiler that
you wish to cross-build.

IIRC, this latter requirement is particularly important for canadian
crosses, but it applies as a general recommendation, and GNAT often
takes advantage of that to use features that will be disregarded by
stage1 (no optimization, no fatal warnings, limited runtime, etc), but
that must be available in later stages and in cross builds, which is
easy to satisfy by using the same compiler version, and which is a given
when bootstrapping.

Of course it isn't always the case that you will run into problems when
deviating from these recommendations, so it's perfectly possible that
you get lucky building it all using compilers that don't meet the
recommendations to get started, but that's counting on luck, not on a
reliable procedure.

See note Prerequisites in the GCC Installation manual for more details.

I hope this helps,

-- 
Alexandre Oliva, happy hacker                https://FSFLA.org/blogs/lxo/
   Free Software Activist                       GNU Toolchain Engineer
Disinformation flourishes because many people care deeply about injustice
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