[Copilot]

wee8’s libstdc++ prebuilt used host glibc 2.39 headers, introducing symbols unavailable in downstream’s glibc 2.31 sysroot. Existing artifact checks verified architecture and C++ ABI, but missed libc compatibility.

• Hermetic GCC

  • Pin GCC 13.4.0 x86_64/aarch64 cross toolchains with glibc 2.26-built target runtimes.
  • Use the shared glibc 2.31 sysroot; source C++ headers, runtimes, and GCC CRT objects from the compiler.
  • Link libstdc++/libgcc statically; preserve platform selection and registration ordering.

• One sysroot

  • Remove the libstdc++ variant, PPA installation, and associated release metadata plumbing.
  • Preserve base archive names and hashes; document migration.

• Compatibility checks

  • Check every wee8 archive member for GLIBC requirements above 2.31 and forbidden newer entry points.
  • Add gcc CI checks for linked libc requirements, static runtime linkage, and toolchain path resolution.

• wee8 rollout

  • Enable aarch64/libstdc++ packaging, bringing the matrix to four variants.
  • Follow-up: regenerate both libstdc++ archives and refresh their hashes in the next bins-v* release before downstream consumption. Keep the unpublished aarch64 prebuilt explicitly incompatible.
  • Full Bazel/wee8 validation remains blocked locally by the unrelated Sequoia fetch from inaccessible gitlab.com.