[Buildroot] Why does host-boost contain only a minimal selection?

[Anders Norman <norman.anders@gmail.com>]

On 10/13/2015 02:44 PM, Thomas Petazzoni wrote:
> Hello Anders,
> 
> On Tue, 13 Oct 2015 11:40:48 +0200, Anders Norman wrote:
> 
>> I have a system set up where I build both natively (for running unit
>> tests) and cross. My application uses libboost (package/boost) and fails
>> to build natively because the linker can't find libboost-filesystem.so.
>> I investigated the issue and find the following in package/boost/boost.mk:
>>
>> # keep host variant as minimal as possible
>> HOST_BOOST_FLAGS = --without-icu --without-libraries=$(subst
>> $(space),$(comma),atomic chrono context coroutine date_time exception
>> filesystem graph graph_parallel iostreams locale log math mpi
>> program_options python random regex serialization signals system test
>> thread timer wave)
>>
>> I guess this is why my host-boost does not contain the filesystem part.
>> What is the reason for removing almost all parts of host-boost when the
>> individual selection flags are already present and used correctly for
>> the cross build?
> 
> The point of most host-* packages is simply to allow building tools
> that are needed to build things for the target. So if a minimal
> configuration of Boost is sufficient to build the Boost things on the
> host that are needed to build the things for the target, then we prefer
> to have such a minimal configuration that is faster to build.
> 
> We do not intend to have the configuration of all host packages match
> the one of the target packages.
> 
> If you want to run your unit tests natively, then you should have a
> separate Buildroot configuration targetting x86/x86-64, and therefore
> use the target Boost.

OK, that makes sense.