uutils: bump libc 0.2.182 -> 0.2.186 for redox sa_flags c_int ABI

Fixes nix-0.30.1 crate build failure where SaFlags::from_bits_truncate()
expected i32 but libc-0.2.182 declared sa_flags as c_ulong (u64) on redox.
libc-0.2.186+ declares sa_flags as c_int (i32), matching relibc's header.

Also includes:
- Add nproc to feat_os_unix_redox feature list
- Remove redox-specific dev_t shims from fs.rs (now handled by libc)
- Add aarch64 locale workaround in locale.rs

Verified: repo cook uutils -> successful, coreutils ELF64 produced.

recipes/core/uutils/redox.patch

@@ -1,5 +1,21 @@
+diff --git a/Cargo.lock b/Cargo.lock
+index ba385a0d2..2b38f508e 100644
+--- a/Cargo.lock
++++ b/Cargo.lock
+@@ -1768,9 +1768,9 @@ checksum = "bbd2bcb4c963f2ddae06a2efc7e9f3591312473c50c6685e1f298068316e66fe"
+ 
+ [[package]]
+ name = "libc"
+-version = "0.2.182"
++version = "0.2.186"
+ source = "registry+https://github.com/rust-lang/crates.io-index"
+-checksum = "6800badb6cb2082ffd7b6a67e6125bb39f18782f793520caee8cb8846be06112"
++checksum = "68ab91017fe16c622486840e4c83c9a37afeff978bd239b5293d61ece587de66"
+ 
+ [[package]]
+ name = "libloading"
 diff --git a/Cargo.toml b/Cargo.toml
-index 5f417bd42..b7b895a9c 100644
+index 5f417bd42..9dfc6ea7d 100644
 --- a/Cargo.toml
 +++ b/Cargo.toml
 @@ -326,6 +326,7 @@ feat_os_unix_redox = [
@@ -10,6 +26,15 @@ index 5f417bd42..b7b895a9c 100644
    "stat",
    "uname",
  ]
+@@ -402,7 +403,7 @@ itertools = "0.14.0"
+ itoa = "1.0.15"
+ jiff = "0.2.18"
+ jiff-icu = "0.2.2"
+-libc = "0.2.172"
++libc = "0.2.186"
+ lscolors = { version = "0.21.0", default-features = false, features = [
+   "gnu_legacy",
+ ] }
 diff --git a/src/uucore/src/lib/features/fs.rs b/src/uucore/src/lib/features/fs.rs
 index fd1f30303..c508f6b9b 100644
 --- a/src/uucore/src/lib/features/fs.rs