guix: use GCC 12.3.0
Summary:
Retain native GCC 10 toolchain for macOS, to prevent compile failures in native tools (this will be removed entirely when we tansition to LLD). Update the vmov-alignment patch, for changes in GCC 12.
Backport of core#27897.
Depends on D17232.
Test Plan: Run the guix builds.
Reviewers: #bitcoin_abc, PiRK
Reviewed By: #bitcoin_abc, PiRK
Differential Revision: https://reviews.bitcoinabc.org/D17233