Aliasing violation in boost-1.85 (container)

Hi,

boost-1.85's container module has an aliasing violation so it may well be miscompiled and give bad results.

See the following:
* https://bugs.gentoo.org/932780
* https://bugs.gentoo.org/933289
* https://github.com/boostorg/container/issues/252
* https://github.com/boostorg/container/issues/281

The upstream fix is https://github.com/boostorg/container/commit/20ad12f20e661978e90dc7f36d8ab8ac05e5a5a9.

The backport we applied in Gentoo (mirror) is
https://github.com/gentoo/gentoo/commit/4bbea521152678132cf0b02e3a152481523b3078.

best,
sam