Index: head/sys/sys/sysctl.h
===================================================================
--- head/sys/sys/sysctl.h
+++ head/sys/sys/sysctl.h
@@ -156,8 +156,7 @@
 #define	REQ_WIRED	2
 
 /* definitions for sysctl_req 'flags' member */
-#if defined(__aarch64__) || defined(__amd64__) || defined(__powerpc64__) ||\
-    (defined(__mips__) && defined(__mips_n64))
+#ifdef COMPAT_FREEBSD32
 #define	SCTL_MASK32	1	/* 32 bit emulation */
 #endif