Re: Problem with removing <config.h> from gen-scmconfig when cross-compiling

[ludo@gnu.org (Ludovic Courtès)]

Mark H Weaver <mhw@netris.org> skribis:

> ludo@gnu.org (Ludovic Courtès) writes:
>
>> Mark H Weaver <mhw@netris.org> skribis:
>>
>>> Commit 8cb0d6d7fa9aaac316c29a64c541336b51b6f93d "build: Don't include
>>> <config.h> in native programs when cross-compiling." apparently broke
>>> cross-compiling.  Madsy on #guile, who successfully cross-compiled
>>> e1bb79f for mingw, ran into this problem with 21a7ba9:
>>>
>>> make[1]: Entering directory `/home/madsy/mingw/home/madsy/test/guile-2.0.9.f239-21a7b-dirty/libguile'
>>>   GEN      gen-scmconfig.o
>>> gen-scmconfig.c: In function 'main':
>>> gen-scmconfig.c:245:39: error: 'SIZEOF_CHAR' undeclared (first use in this function)
>>> gen-scmconfig.c:245:39: note: each undeclared identifier is reported only once for each function it appears in
>>
>> Arrgggh, indeed, sorry!
>>
>> We should revert that patch, but then I’m not sure how to properly fix
>> the initial problem, which is that gen-scmconfig.c ends up using
>> Gnulib’s <stdio.h> etc.
>
> Madsy told me that the only problem he had when cross-compiling e1bb79f
> was in c-tokenize.c.  He worked around it by simply removing "#include
> <config.h>" from that file.  gen-scmconfig.c was not a problem.
>
> The specific problem was that c-tokenize.c includes <stdlib.h>,
> but gen-scmconfig.c doesn't include <stdlib.h>.
>
> I agree that this is fragile and should be reworked somehow, but for
> 2.0.10, I wonder if we could just revert the part of 8cb0d6d having to
> do with gen-scmconfig.c.
>
> What do you think?

You’re right.  So for 2.0.10, just revert, and then remove #include
<config.h> altogether in c-tokenize.lex with a comment saying why.

Could you do that?

> Didn't hydra.nixos.org do MinGW cross-builds of Guile in the past?
> If so, what happened to those?

Yes, we had that, but I removed it in
<http://git.sv.gnu.org/cgit/hydra-recipes.git/commit/?id=aea7182a62f8c6f7a04a7e89fbdd59155d5f34ff>
because the MinGW cross toolchain in Nixpkgs had bitrot.  :-/

(BTW, we can test cross-compilation to GNU/Linux with
guix build guile --with-source=guile-2.0.9.xyz.tar.xz --target=mips64el-linux-gnu.)

Ludo’.