================ @@ -86,17 +86,37 @@ int fcntl(int fd, int cmd, void *arg) { libc_errno = -ret; return -1; } + case F_GETLK: { +#if defined(SYS_fcntl64) ---------------- lntue wrote: nit `#ifdef` is fine. https://github.com/llvm/llvm-project/pull/99675