Haiku: Add utmpx functions

Author: GrayJack

src/unix/haiku/mod.rs

@@ -1622,6 +1622,12 @@ extern "C" {
     ) -> ::pid_t;
     pub fn sethostname(name: *const ::c_char, len: ::size_t) -> ::c_int;
     pub fn uname(buf: *mut ::utsname) -> ::c_int;
+    pub fn getutxent() -> *mut utmpx;
+    pub fn getutxid(ut: *const utmpx) -> *mut utmpx;
+    pub fn getutxline(ut: *const utmpx) -> *mut utmpx;
+    pub fn pututxline(ut: *const utmpx) -> *mut utmpx;
+    pub fn setutxent();
+    pub fn endutxent();
 }
 
 cfg_if! {