Add missing utmpx apis for linux musl

Close rust-lang#4322

Signed-off-by: Etienne Cordonnier <[email protected]>

Author: Ecordonnier

libc-test/semver/linux-musl.txt

@@ -1,3 +1,4 @@
+ACCOUNTING
 AF_IB
 AF_MPLS
 AF_XDP
@@ -37,6 +38,9 @@ RWF_HIPRI
 RWF_NOWAIT
 RWF_SYNC
 USER_PROCESS
+UT_HOSTSIZE
+UT_LINESIZE
+UT_NAMESIZE
 _CS_V6_ENV
 _CS_V7_ENV
 adjtimex
@@ -82,3 +86,4 @@ reallocarray
 setutxent
 tcp_info
 timex
+utmpxname

src/unix/linux_like/linux/musl/mod.rs

@@ -656,7 +656,7 @@ pub const INIT_PROCESS: c_short = 5;
 pub const LOGIN_PROCESS: c_short = 6;
 pub const USER_PROCESS: c_short = 7;
 pub const DEAD_PROCESS: c_short = 8;
-// musl does not define ACCOUNTING
+pub const ACCOUNTING: c_short = 9;
 
 pub const SFD_CLOEXEC: c_int = 0x080000;
 
@@ -888,6 +888,10 @@ pub const _CS_V7_ENV: c_int = 1149;
 
 pub const CLONE_NEWTIME: c_int = 0x80;
 
+pub const UT_HOSTSIZE: usize = 256;
+pub const UT_LINESIZE: usize = 32;
+pub const UT_NAMESIZE: usize = 32;
+
 cfg_if! {
     if #[cfg(target_arch = "s390x")] {
         pub const POSIX_FADV_DONTNEED: c_int = 6;
@@ -990,6 +994,7 @@ extern "C" {
     pub fn pututxline(ut: *const utmpx) -> *mut utmpx;
     pub fn setutxent();
     pub fn endutxent();
+    pub fn utmpxname(file: *const c_char) -> c_int;
 }
 
 // Alias <foo> to <foo>64 to mimic glibc's LFS64 support