Surprisingly, GNU/kFreeBSD has /proc/loadavg and no nlist(3).

diff -ruNp inn-1.7.2.orig/nnrpd/loadave.c inn-1.7.2/nnrpd/loadave.c
--- inn-1.7.2.orig/nnrpd/loadave.c	1997-12-09 00:48:50.000000000 +0100
+++ inn-1.7.2/nnrpd/loadave.c	2007-08-07 21:27:09.000000000 +0200
@@ -7,7 +7,7 @@
 #include "clibrary.h"
 #include "nnrpd.h"
 #if	NNRP_LOADLIMIT > 0
-#ifdef linux
+#ifdef __GLIBC__
 
 /*
 **  Get the current load average as an integer.
