Re: [gentoo-user] python build fail; undefined reference to pthread_* and sem_*

[Mike Gilbert]

On Wed, Oct 11, 2017 at 11:50 AM, Mike Gilbert <floppym@g.o> wrote:
> On Wed, Oct 11, 2017 at 12:16 AM, Walter Dnes <waltdnes@××××××××.org> wrote:
>>   This is happening with both python 2.7.12 and 3.4.5 on a 32-bit x86
>> system.  Build logs are attached, along with "emerge --info" output.  I
>> can't find anything relevant in bugzilla.
>
> From the build log for 3.4.5:
>
> checking whether pthreads are available without options... yes
>
> This is clearly a lie; glibc requires that you pass "-pthread" to gcc
> to enable pthreads. For some reason, configure is mis-detecting this.
>
> I would try rebuilding with minimal CFLAGS.

I can reproduce the issue by adding -fopenmp to my CFLAGS. You can
work around it by adding -fopenmp to LDFLAGS as well.

This is probably a bug in the Python build system; it should probably
be passing CFLAGS to gcc when linking libpython.