[Buildroot] [PATCH 1/1] protobuf/protobuf-c: bump versions

[Yann E. MORIN <yann.morin.1998@free.fr>]

Nimai, All,

On 2015-08-14 11:11 -0400, Nimai Mahajan spake thusly:
> On Fri, Aug 14, 2015 at 8:37 AM, Yann E. MORIN <yann.morin.1998@free.fr> wrote:
[--SNIP--]
> >     http://autobuild.buildroot.org/toolchains/configs/br-arm-full-static.config
> >     http://autobuild.buildroot.org/toolchains/configs/br-arm-cortex-a9-musl.config
[--SNIP--]
> Thanks for the suggestion! I didn't know autobuilder had prebuilt
> external toolchains for anyone to use publicly;

Yes, it is a little-known fact. Even I often forgets about it from time
to time... :-/

> protobuf-c v1.1.1 builds successfully with all toolchains ...

Good. Please provide a separate patch just to bump protobuf-c, then.

> protobuf    v2.6.1 builds successfully with everything except uClibc
> static, where it fails with this:
> 
> D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -c
> google/protobuf/stubs/atomicops_internals_x86_gcc.cc -o
> google/protobuf/stubs/atomicops_internals_x86_gcc.o
> google/protobuf/stubs/common.cc:48:2: error: #error "No suitable
> threading library available."
>  #error "No suitable threading library available."
>   ^
[--SNIP--]
> Seems to be a threading library issue but toolchain has NPTL thread
> support I believe so not sure why that is.

In fact, it is not a threading issue. If you look closely at the
config.log, you'll see that pthreads are properly detected, but that a
further check about shared libs is broken, see:

    http://autobuild.buildroot.org/results/3ef/3efb86c7e8ec2db5d953d634470cafae79bd34cf/protobuf-v2.5.0/config.log

Most notably:

    checking for the pthreads library -lpthreads... no
    checking whether pthreads work without any flags... no
    checking whether pthreads work with -Kthread... no
    checking whether pthreads work with -kthread... no
    checking for the pthreads library -llthread... no
    checking whether pthreads work with -pthread... yes
    checking for joinable pthread attribute... PTHREAD_CREATE_JOINABLE
    checking if more special flags are required for pthreads... no
    checking whether to check for GCC pthread/shared inconsistencies... yes
    checking whether -pthread is sufficient with -shared... no
    checking whether -lpthread fixes that... no
    checking whether -lc_r fixes that... no
    configure: WARNING: Impossible to determine how to use pthreads with shared libraries
    checking whether what we have so far is sufficient with -nostdlib... no
    checking whether -lpthread saves the day... no
    configure: WARNING: Impossible to determine how to use pthreads with shared libraries and -nostdlib

So, it's those checks about "GCC pthread/shared inconsistencies" that
are broken: it forcibly tries a shared link, even thoug h we are asking
for static link.

It all happens in an m4 macro, in protobuf-v2.5.0/m4/acx_pthread.m4,
around lines 239..375.

Fixing this macros is a huge "enterntainment" ;-]

So I think it is musch easier to just mark the package as not being
availble for static-only builds...

Regards,
Yann E. MORIN.

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