diff --git a/lib/libc/rpc/Makefile.inc b/lib/libc/rpc/Makefile.inc
index 9f3bb453c0b6..5ca9bd3757c0 100644
--- a/lib/libc/rpc/Makefile.inc
+++ b/lib/libc/rpc/Makefile.inc
@@ -2,7 +2,7 @@
 # $FreeBSD$
 
 .PATH: ${LIBC_SRCTOP}/rpc ${LIBC_SRCTOP}/.
-CONFS=	rpc/netconfig rpc/rpc
+CONFS+=	rpc/netconfig rpc/rpc
 SRCS+=	auth_none.c auth_unix.c authunix_prot.c bindresvport.c clnt_bcast.c \
 	clnt_dg.c clnt_generic.c clnt_perror.c clnt_raw.c clnt_simple.c \
 	clnt_vc.c rpc_dtablesize.c getnetconfig.c getnetpath.c getrpcent.c \