Re: avr-gcc

[Andy Wingo]

Hi :)

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

> Andy Wingo writes:
>
>> Or is there some special logic which is applying to CPATH which is not
>> applying to C_INCLUDE_PATH?
>
> Ah, yes; CPATH is not used when cross building, instead CROSS_CPATH is
> used.

Ah, I see.  I guess that's the essential difference.

>> 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.

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.

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 :)

Happy hacking,

Andy

ps. Thank you for all of your work here, Jan!