In the new GNU RCS port the checkout during grcsdiff failed because

it cannot find a /usr/local/bin/rcs binary.  The peer_super struct
is used to locate the grcs binary for various operations.  So patch
the "g" prefix there.
OK ajacoutot@

devel/grcs/Makefile

@@ -1,9 +1,10 @@
-# $OpenBSD: Makefile,v 1.7 2016/03/05 14:30:47 rpe Exp $
+# $OpenBSD: Makefile,v 1.8 2016/03/19 13:02:48 bluhm Exp $
 
 COMMENT=	GNU versions of the rcs utilities
 
 DISTNAME=	rcs-5.9.4
 PKGNAME=	g${DISTNAME}
+REVISION=	1
 
 CATEGORIES=	devel
 

devel/grcs/patches/patch-src_b-peer_c

@@ -0,0 +1,12 @@
+$OpenBSD: patch-src_b-peer_c,v 1.1 2016/03/19 13:02:48 bluhm Exp $
+--- src/b-peer.c.orig	Fri Jan  9 10:40:02 2015
++++ src/b-peer.c	Wed Mar 16 19:35:59 2016
+@@ -25,7 +25,7 @@
+ #include "b-complain.h"
+ #include "b-divvy.h"
+ 
+-struct symdef peer_super = { .meaningful = "rcs", .underlying = NULL };
++struct symdef peer_super = { .meaningful = "grcs", .underlying = NULL };
+ 
+ const char *
+ one_beyond_last_dir_sep (const char *name)