[Buildroot] [RFC] package/boost: fix powerpc uClibc build issue

[Romain Naour <romain.naour@openwide.fr>]

Hi Thomas,

Le 15/05/2015 20:42, Thomas Petazzoni a ?crit :
> Dear Romain Naour,
> 
> On Fri, 15 May 2015 19:00:07 +0200, Romain Naour wrote:
>> With powerpc target and uClibc toolchain the spirit library doesn't
>> build properly due to an invalid field access.
>>
>> The "bits" field is intended only for internal use in
>> include/boost/math/special_functions/sign.hpp not from
>> include/boost/spirit/home/support/detail/sign.hpp.
>>
>> Simply call (boost::math::changesign)(x) from
>> include/boost/spirit/home/support/detail/sign.hpp to fixes this.
>>
>> Fixes:
>> http://autobuild.buildroot.net/results/be1/be1069e8528d299f487f431f7e2d793413ccbab8/
>>
>> And many more.
>>
>> Signed-off-by: Romain Naour <romain.naour@openwide.fr>
>> ---
>> It's not clear why this issue is only trigged by powerpc
>> with uClibc toolchain.
>> Also, it's a pity that the spirit library doesn't use directly
>> math library instead of using a wrapper.
> 
> My opinion is that this patch is too tricky to be committed without
> being checked by upstream Boost developers, especially since there is
> no explanation as to why the problem occurs only on PowerPC.
> 
> I would prefer to disable boost-log on PowerPC/uClibc, as proposed by
> the patch I submitted shortly after this one.

I'm agree with your proposal and I'll wait for upstream comment on this patch:

http://sourceforge.net/p/spirit/mailman/message/34116604/

Best regards,
Romain

> Best regards,
> 
> Thomas
>