jammy-yoga pip install of wheelhouse fails due to gcc failures with lxml and openssl

[Corey Bryant]

As seen in the gate here:
https://review.opendev.org/c/openstack/charm-keystone-saml-mellon/+/847476

ubuntu@juju-c06f0d-zaza-3dacb5a26a26-5:/var/lib/juju/agents/unit-keystone-saml-mellon1-1/charm$ /var/lib/juju/agents/unit-keystone-saml-mellon1-1/.venv/bin/pip install -U --force-reinstall --no-index --no-cache-dir -f wheelhouse asn1crypto==1.5.1 netifaces==0.11.0 idna==3.3 pbr==5.10.0 charms.openstack==0.0.1.dev1 PyYAML==5.3.1 lxml==4.5.0 dnspython==1.16.0 netaddr==0.7.19 charmhelpers==1.1.1.dev37 charms.reactive==1.5.0 cffi==1.15.1 Jinja2==3.0.3 six==1.16.0 pyaml==21.10.1 cryptography==2.3.1 pycparser==2.21 psutil==5.9.1

results in gcc failures such as:

      src/lxml/etree.c: In function ‘__pyx_tp_dealloc_4lxml_5etree__LogEntry’:
      src/lxml/etree.c:221671:5: error: lvalue required as increment operand
      221671 | ++Py_REFCNT(o);
             | ^~

      build/temp.linux-x86_64-3.10/_openssl.c:2707:13: warning: ‘_ssl_thread_locking_function’ defined but not used [-Wunused-function]
       2707 | static void _ssl_thread_locking_function(int mode, int n, const char *file,
            | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
      error: command '/usr/bin/x86_64-linux-gnu-gcc' failed with exit code 1

I'm wondering if these will get fixed up if we move to using newer package versions.

[Corey Bryant (corey.bryant)]

Attaching document with full pip output from a failing unit

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/charm-keystone-saml-mellon/+/870348
Committed: https://opendev.org/openstack/charm-keystone-saml-mellon/commit/832b46a29b59102b1defb962ae31ba6e380042d2
Submitter: "Zuul (22348)"
Branch: stable/ussuri

commit 832b46a29b59102b1defb962ae31ba6e380042d2
Author: Corey Bryant <email address hidden>
Date: Fri Jan 13 15:06:10 2023 -0500

    Pin tox to < 4.0.0

    Tox 4.0.0 was recently released and it has several breaking changes.
    We pin to < 4.0.0 here. We are planning to move forward only on the
    master charm branches.

    Tox is also pinned to < 4.0.0 for stable branches in upstream
    openstack-zuul-jobs as well as in zosci-config. However, the
    requires= section in the charm's tox.ini file ends up installing
    tox>4, wiping out the zuul-pinned tox<4 that was already installed
    installed. This patch fixes that.

    Added libxml2-dev to the list of dependencies in src/layer.yaml, this
    explicit dependency is needed only when deploying on Bionic.

    Related-Bug: #2002788
    Closes-Bug: #1988092
    Change-Id: I4a5a4f3cafebb986c64e54d2a3a0bd048adf0933