Add missing musl utmpx.h constants

Author: andrewliebenow

libc-test/semver/linux-musl.txt

@@ -1,4 +1,14 @@
 # TODO: musl.
+# linux-gnu.txt is alphabetized, but this file is not
+EMPTY
+RUN_LVL
+BOOT_TIME
+NEW_TIME
+OLD_TIME
+INIT_PROCESS
+LOGIN_PROCESS
+USER_PROCESS
+DEAD_PROCESS
 AF_IB
 AF_MPLS
 AF_XDP

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

@@ -628,6 +628,18 @@ pub const MAP_HUGE_16GB: ::c_int = 34 << MAP_HUGE_SHIFT;
 
 pub const MS_RMT_MASK: ::c_ulong = 0x02800051;
 
+// include/utmpx.h
+pub const EMPTY: ::c_short = 0;
+pub const RUN_LVL: ::c_short = 1;
+pub const BOOT_TIME: ::c_short = 2;
+pub const NEW_TIME: ::c_short = 3;
+pub const OLD_TIME: ::c_short = 4;
+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 SFD_CLOEXEC: ::c_int = 0x080000;
 
 pub const NCCS: usize = 32;