diff --git a/local/AGENTS.md b/local/AGENTS.md
index aa5e5baf81..4747bd114f 100644
--- a/local/AGENTS.md
+++ b/local/AGENTS.md
@@ -907,6 +907,7 @@ This rule applies to ALL Cat 2 fork crates:
 | `libredox` | `local/sources/libredox/` | `path = "../../../../../local/sources/libredox"` |
 | `redox-scheme` | `local/sources/redox-scheme/` | `path = "../../../../../local/sources/redox-scheme"` |
 | `redoxfs` | `local/sources/redoxfs/` | `path = "../../../../../local/sources/redoxfs"` |
+| `libc` | `local/sources/libc/` | via `[patch.crates-io]` in the rust workspace — **temporary**, see `local/docs/VENDORED-LIBC-FORK.md` |
 
 **Correct pattern (path dep):**
 ```toml
diff --git a/local/docs/VENDORED-LIBC-FORK.md b/local/docs/VENDORED-LIBC-FORK.md
new file mode 100644
index 0000000000..a9c80ce601
--- /dev/null
+++ b/local/docs/VENDORED-LIBC-FORK.md
@@ -0,0 +1,85 @@
+# Vendored `libc` Fork — Redox `waitid` Surface
+
+**Status:** TEMPORARY. Vendored for as long as it is required; delete once
+upstream `libc` carries the Redox bindings.
+**Location:** `local/sources/libc/`
+**Base:** crates.io `libc` 0.2.189, unmodified except `src/unix/redox/mod.rs`.
+**Established:** 2026-08-03.
+
+Related: `LOCAL-FORK-SUPREMACY-POLICY.md`, `FORK-BUMP-PATCHING-POLICY.md`,
+`local/AGENTS.md` § "Local fork dependency rule".
+
+---
+
+## Why this fork exists
+
+relibc implements the POSIX `waitid` surface in full, but the `libc` crate's
+Redox bindings never exposed it — and still do not as of 0.2.189. Any crate
+that calls `waitid` therefore cannot build for `x86_64-unknown-redox`:
+
+```
+error[E0531]: cannot find unit struct, unit variant or constant
+              `CLD_EXITED` in crate `libc`
+error[E0531]: cannot find unit struct, unit variant or constant
+              `P_ALL` in crate `libc`
+```
+
+That breaks `nix`, and through it `ctrlc` and rustc's bootstrap tooling — which
+is what blocked `rust-native`, and with it the whole native toolchain
+(`gcc-native`, `llvm-native`, `rust-native`) that `config/redbear-full.toml`
+requires.
+
+This is a **binding gap, not a missing implementation**. Every symbol added
+here is already real in relibc:
+
+| Symbol | relibc source | Evidence |
+|---|---|---|
+| `waitid()` | `src/header/sys_wait/mod.rs:153` | `nm libc.a` → `T waitid` |
+| `idtype_t` | `src/header/sys_wait/mod.rs:17` | `pub type idtype_t = c_int` |
+| `P_ALL` / `P_PID` / `P_PGID` | `src/header/sys_wait/mod.rs:20-24` | `0` / `1` / `2` |
+| `CLD_*` (6) | `include/signal.h:457-467` | `CLD_EXITED 1` … `CLD_CONTINUED 6` |
+
+Values and types are taken from **relibc**, not from Linux. Redox's `idtype_t`
+is `c_int` where glibc uses an enum, and copying the Linux definitions would
+have produced a silently wrong ABI.
+
+## What is actually changed
+
+One file: `src/unix/redox/mod.rs`. Every other target is byte-for-byte upstream
+0.2.189, so host builds and all non-Redox targets are unaffected.
+
+## How it is wired
+
+`[patch.crates-io]` in the rust workspace, carried durably as
+`local/patches/rust/02-libc-redox-fork.patch`:
+
+```toml
+libc = { path = "../../../../local/sources/libc" }
+```
+
+`+rb` build metadata is what makes this safe: it leaves the upstream semver
+(`0.2.189`) intact, so `^0.2` requirements still resolve. A `-rb` suffix would
+be read as a pre-release and fail to satisfy them — see `local/AGENTS.md`
+§ "Version conventions".
+
+Registered in `local/fork-upstream-map.toml` as a `snapshot` fork (its history
+comes from the registry, not a git clone), with `src/unix/redox/mod.rs` on the
+declarative expected-differ list in `verify-fork-versions.sh` so the content
+check stays meaningful rather than being blanket-skipped.
+
+## Retiring this fork
+
+Upstream-reportable: the gap belongs in the `libc` crate. When upstream exposes
+the Redox `waitid` surface:
+
+1. Confirm `CLD_*`, `P_*`, `idtype_t` and `waitid` are all present in
+   `src/unix/redox/mod.rs` for the version being resolved.
+2. Drop `02-libc-redox-fork.patch` from `recipes/dev/rust/recipe.toml`.
+3. Remove the `libc` row from `local/fork-upstream-map.toml` and both
+   `libc)` arms from `verify-fork-versions.sh`.
+4. Delete `local/sources/libc/`.
+5. Rebuild `rust-native` to confirm `nix` still compiles.
+
+Until then this fork stays. Bumping it follows
+`FORK-BUMP-PATCHING-POLICY.md`: re-vendor the newer upstream and re-apply the
+Redox block — never carry the old base forward.
diff --git a/local/fork-upstream-map.toml b/local/fork-upstream-map.toml
index c93fe0e1a7..6bc091b365 100644
--- a/local/fork-upstream-map.toml
+++ b/local/fork-upstream-map.toml
@@ -39,3 +39,9 @@ bootloader   https://gitlab.redox-os.org/redox-os/bootloader.git   1.0.0     div
 installer    https://gitlab.redox-os.org/redox-os/installer.git    0.2.42    diverged  # fork has TUI GUI + Red Bear config additions not in upstream 0.2.42 -- content check advisory only; full rebase is Phase 2.4+ work
 userutils    https://gitlab.redox-os.org/redox-os/userutils.git    0.1.0     snapshot
 base         https://gitlab.redox-os.org/redox-os/base.git         main       tracked
+# Vendored from the crates.io registry (unrelated git history -> snapshot).
+# Divergence is confined to src/unix/redox/mod.rs, which exposes the waitid
+# surface relibc already implements and the libc crate still omits as of
+# 0.2.189. TEMPORARY: drop this fork once upstream libc carries the Redox
+# bindings. See local/docs/VENDORED-LIBC-FORK.md.
+libc         https://github.com/rust-lang/libc.git                 0.2.189    snapshot
diff --git a/local/scripts/verify-fork-versions.sh b/local/scripts/verify-fork-versions.sh
index 9531b50be8..ef8d1d35a3 100755
--- a/local/scripts/verify-fork-versions.sh
+++ b/local/scripts/verify-fork-versions.sh
@@ -190,7 +190,8 @@ for fork_dir in local/sources/*/; do
     # whose local-patches/ dir is empty but the fork has legitimately
     # diverged via direct commits need explicit entries here.
     case "$fork_name" in
-        libredox)  expected_differ+=("src/lib.rs") ;;  # F_DUPFD_CLOEXEC + AcpiVerb at commit 6908adc
+        libredox)  expected_differ+=("src/lib.rs") ;;
+        libc)      expected_differ+=("src/unix/redox/mod.rs") ;;  # waitid/CLD_*/P_* surface  # F_DUPFD_CLOEXEC + AcpiVerb at commit 6908adc
         redoxfs)   expected_differ+=("src/filesystem.rs" "src/record.rs" \
                                      "src/mount/redox/mod.rs" "src/mount/redox/scheme.rs") ;;
                    # filesystem.rs + record.rs: a936d00 (Red Bear) import Vec from
@@ -241,7 +242,8 @@ for fork_dir in local/sources/*/; do
         # local-patches/ dir is empty (no patch files) but the fork
         # itself has legitimately diverged via direct commits.
         case "$fork_name" in
-            libredox)  patch_modified_files+=("src/lib.rs") ;;  # F_DUPFD_CLOEXEC + AcpiVerb
+            libredox)  patch_modified_files+=("src/lib.rs") ;;
+            libc)      patch_modified_files+=("src/unix/redox/mod.rs") ;;  # F_DUPFD_CLOEXEC + AcpiVerb
             redoxfs)   patch_modified_files+=("src/filesystem.rs" "src/record.rs" \
                                               "src/mount/redox/mod.rs" "src/mount/redox/scheme.rs") ;;
         esac