The fork was an unmapped tree -- verify-fork-versions.sh reported
'libc NOT-MAPPED'. Register it properly so it is governed like every other
Cat 2 fork rather than sitting outside the checks:
- local/fork-upstream-map.toml: libc -> rust-lang/libc 0.2.189, snapshot
mode (vendored from the registry, so its history is unrelated to
upstream's), with the temporary status noted inline.
- verify-fork-versions.sh: src/unix/redox/mod.rs added to the declarative
expected-differ list, so the content check keeps verifying the rest of
the tree instead of being blanket-skipped.
- local/docs/VENDORED-LIBC-FORK.md: what the fork adds, the relibc source
and evidence for every symbol, why the values come from relibc rather
than Linux (Redox's idtype_t is c_int where glibc uses an enum), and a
five-step retirement procedure.
- local/AGENTS.md: listed in the fork table, marked temporary.
Kept vendored for as long as it is required. The gap is upstream-
reportable and belongs in the libc crate.
vasilito
09ba5201f4