diff --git a/lib/libc/sys/mmap.2 b/lib/libc/sys/mmap.2
index 89bb894ccca1..7e0affc029a6 100644
--- a/lib/libc/sys/mmap.2
+++ b/lib/libc/sys/mmap.2
@@ -330,7 +330,8 @@ was specified and insufficient memory was available.
 .Xr msync 2 ,
 .Xr munlock 2 ,
 .Xr munmap 2 ,
-.Xr getpagesize 3
+.Xr getpagesize 3 ,
+.Xr make.conf 5
 .Sh BUGS
 .Fa len
 is limited to 2GB.  Mmapping slightly more than 2GB doesn't work, but