fix: pin libc to 0.2.178 to fix loongarch64-musl build failure

libc >= 0.2.179 enables `musl_v1_2_3` for loongarch64 which changes
`struct stat` fields from `st_atime`/`st_mtime`/`st_ctime` to
`st_atim`/`st_mtim`/`st_ctim`. This breaks rustix 0.38.42 on
loongarch64-unknown-linux-musl target.

Reference: rust-lang/libc#4939

Co-Authored-By: Claude Opus 4.6 <[email protected]>

Author: hustcer

Cargo.lock

@@ -112,7 +112,7 @@ is_executable = "1.0"
 itertools = "0.14"
 lean_string = { version = "0.5", features = ["serde"] }
 lexopt = "0.3.1"
-libc = "0.2"
+libc = "=0.2.178" # Pinned to avoid loongarch64 build failure with libc >= 0.2.179 (rust-lang/libc#4939)
 libproc = "0.14"
 log = "0.4"
 lru = "0.16"