Currently, Linux builds are performed with a different toolchain (GCC 7) than macOS and Windows builds, which use GCC 10. This task involves changing the build system to use GCC 10 for Linux builds.
From the original issue:
"Currently, our Linux Guix builds differ from macOS and Windows, in that they use a native GCC 7 toolchain (i.e to build glibc) and then GCC 10 to build depends and Bitcoin Core. Migrating the Linux builds to a native GCC 10 toolchain will unify us on a single native compiler and very likely solve #22458.
The main issue with performing this migration is building older glibcs (2.24, 2.27) with GCC 10. When I last tried, it was apparent that either warnings produced by the newer GCC would need to be suppressed (as glibc is built -Werror), or patches to glibc would need to be backported to address any issues."