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

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

Hi

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?

Anders