unix: add constants for netlink/audit

Change-Id: Idaa02498b43360fa647d52423bc2f4c0cd5a9523
Reviewed-on: https://go-review.googlesource.com/c/sys/+/416754
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>

unix/mkerrors.sh

@@ -203,6 +203,7 @@ struct ltchars {
 #include <sys/timerfd.h>
 #include <sys/uio.h>
 #include <sys/xattr.h>
+#include <linux/audit.h>
 #include <linux/bpf.h>
 #include <linux/can.h>
 #include <linux/can/error.h>
@@ -554,6 +555,7 @@ ccflags="$@"
 		$2 ~ /^CLONE_[A-Z_]+/ ||
 		$2 !~ /^(BPF_TIMEVAL|BPF_FIB_LOOKUP_[A-Z]+)$/ &&
 		$2 ~ /^(BPF|DLT)_/ ||
+		$2 ~ /^AUDIT_/ ||
 		$2 ~ /^(CLOCK|TIMER)_/ ||
 		$2 ~ /^CAN_/ ||
 		$2 ~ /^CAP_/ ||
@@ -576,7 +578,6 @@ ccflags="$@"
 		$2 ~ /^SEEK_/ ||
 		$2 ~ /^SPLICE_/ ||
 		$2 ~ /^SYNC_FILE_RANGE_/ ||
-		$2 !~ /^AUDIT_RECORD_MAGIC/ &&
 		$2 !~ /IOC_MAGIC/ &&
 		$2 ~ /^[A-Z][A-Z0-9_]+_MAGIC2?$/ ||
 		$2 ~ /^(VM|VMADDR)_/ ||