diff --git a/share/mk/bsd.own.mk b/share/mk/bsd.own.mk
index b604011b9159..c560480c5707 100644
--- a/share/mk/bsd.own.mk
+++ b/share/mk/bsd.own.mk
@@ -1,4 +1,4 @@
-#	$NetBSD: bsd.own.mk,v 1.1105 2019/03/04 01:14:31 mrg Exp $
+#	$NetBSD: bsd.own.mk,v 1.1106 2019/03/04 17:32:46 christos Exp $
 
 # This needs to be before bsd.init.mk
 .if defined(BSD_MK_COMPAT_FILE)
@@ -168,6 +168,16 @@ EXTERNAL_BINUTILS_SUBDIR=	binutils.old
 EXTERNAL_BINUTILS_SUBDIR=	/does/not/exist
 .endif
 
+#
+# What version of jemalloc we use (100 is the one
+# built-in to libc from 2005 (pre version 3).
+#
+.if ${MACHINE_CPU} == "x86_64"
+HAVE_JEMALLOC?=		510
+.else
+HAVE_JEMALLOC?=		100
+.endif
+
 .if empty(.MAKEFLAGS:tW:M*-V .OBJDIR*)
 .if defined(MAKEOBJDIRPREFIX) || defined(MAKEOBJDIR)
 PRINTOBJDIR=	${MAKE} -r -V .OBJDIR -f /dev/null xxx