Re: Question about build warnings.

[Ian Lance Taylor <iant at google dot com>]

Georg-Johann Lay <avr@gjlay.de> writes:

> Ian Lance Taylor schrieb:
>> Georg-Johann Lay <avr@gjlay.de> writes:
>> 
>>> Hi, when building gcc I get bunch of build warnings like these:
>> 
>> This is normal when building stage 1.  You should not see any warnings
>> when building stages 2 or 3.
>> 
>> The warnings occur mainly on gcc diagnostic functions.  The definitions
>> of the control sequences used in these functions change from time to
>> time.  This then triggers warnings when building stage 1 with an older
>> version of gcc.  These warnings are unimportant.
>> 
>> Ian
>
> The background is bug reports like
>
> http://gcc.gnu.org/PR48896#c2
>
> where for some people the build fails because of warnings that I don't
> even see with reasonable version of build GCC.

Looks like Joern was building a cross-compiler with -Werror.  In
general, doing that means that you have to build the cross-compiler with
the same version of the compiler, configured and built as a native
compiler.  Most people just don't use -Werror for a cross-compiler.
Joern is an experienced gcc developer, so I would guess that he was in
fact using the same version of the compiler, and was reporting errors
that occurred nevertheless.  In comment #2 you are using a different
version of the compiler.

I hope that makes sense.

Ian