Re: avr-gcc

[Ludovic Courtès]

Andy Wingo <address@hidden> skribis:

> On Fri 15 Apr 2016 14:44, Jan Nieuwenhuizen <address@hidden> writes:
>
>> Andy Wingo writes:

[...]

>>> Basically in Guix we should, IMO, always be working on C_INCLUDE_PATH
>>> and friends, and never on CPATH.
>>
>> I'm guessing that could work; would could try to change the above patch
>> (in gcc-cross-environment-variables.patch) to handle C*_INCLUDE_PATH and
>> introduce CROSS_C*_INCLUDE_PATH.
>>
>> I just wonder if there was another reason for cross builds to choose
>> CPATH/CROSS_CPATH instead of C_*INCLUDE_PATH.  Apart maybe from the
>> fact that we would need to handle all `*' where CPATH works for all
>> languages.

It just happened to be easier to take care of one variable than to take
care of all of them.  (At the time we also used CPATH for the native
GCC.)

> Yeah let's give this a try instead.  Probably we should support
> CROSS_ variants of all of these include paths: CPATH, C_INCLUDE_PATH,
> and so on.

Sounds good to me!

> I admit I don't understand why the CROSS_ paths are needed.  But I
> haven't looked into it and if I don't need to know, I am happy to remain
> ignorant :)

This is so that we can specify different search paths for the native
compiler and for the cross compiler, which is necessary when the coexist
in the same environment: <http://gcc.gnu.org/ml/gcc/2013-02/msg00124.html>.

Thanks,
Ludo’.