[yocto] Python cryptography failing due to undefined symbol: pthread_atfork

[Alan Martinovic]

I have confirmed that no `-pthread` flags are being set for building
python-cryptography.

Running the following:

    bitbake python-cryptography -c do_compile
    bitbake python-cryptography -c devshell
    grep pthread ../temp/run.do_compile

gives no returns.
Also there isn't a mention of it when doing a build in full
verbose:

    bitbake python-cryptography -c cleanall
    bitbake python-cryptography -vvv | vi -


On the target the symbol is identified as missing (NOTYPE):

    ~# readelf -a
/usr/lib/python3.5/site-packages/cryptography/hazmat/bindings/_openssl.abi3.so
| grep pthread_atfork
    000aebb4  0002d916 R_ARM_JUMP_SLOT   00000000   pthread_atfork
       729: 00000000     0 NOTYPE  GLOBAL DEFAULT  UND pthread_atfork


My current goal is to extend the recipe with the `-pthread` so that
it's there when
the '_openssl' extension is being built.
Still open to suggestions.


A thing that seems to be underlying my assumption is that the recipe
for python-cryptography
hasn't actually changed between Morty (where it worked) and Rocko...

On Thu, Dec 21, 2017 at 6:17 PM, Alan Martinovic
<alan.martinovic at senic.com> wrote:
> Hi there,
> just did a migration to Rocko and am witnessing"
>
>     root at device:~# python3
>     Python 3.5.3 (default, Dec 20 2017, 02:02:22)
>     [GCC 7.2.0] on linux
>     Type "help", "copyright", "credits" or "license" for more information.
>     >>> from cryptography.hazmat.bindings._openssl import ffi, lib
>     Traceback (most recent call last):
>       File "<stdin>", line 1, in <module>
>     ImportError:
> /usr/lib/python3.5/site-packages/cryptography/hazmat/bindings/_openssl.abi3.so:
> undefined symbol: pthread_atfork
>
>
> Have tried both the recipe that comes with Rocko
> and master of meta-openembedded.
>
> Seems to be the same bug as this one:
>
> https://bugs.gentoo.org/630578
>
> resolved with this patch:
>
> https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=c824d1c44fcf4556de21d2c8b8ae3732b0fc0c5b
>
> Can someone provide hints on what would that translate to
>  for the python cryptography recipe?