Disable GNU rcs by default

All remaining tools using rcs has been switched to directly use diff3(1):
- etcupdate(8)
- freebsd-update(8)

Note that the ident(1) tool is been already replaced long ago with a BSD
licensed version, as such it remains installed.

GNU rcs is still available from ports:
- rcs: newer GPLv3 version
- rcs57: the latest version from base (GPLv2)

UPDATING

@@ -31,6 +31,10 @@ NOTE TO PEOPLE WHO THINK THAT FreeBSD 12.x IS SLOW:
 	disable the most expensive debugging functionality run
 	"ln -s 'abort:false,junk:false' /etc/malloc.conf".)
 
+20160918:
+	GNU rcs has been turned off by default. It can (temporary) be built
+	again by adding WITH_RCS knob in src.conf.
+
 20160918:
 	The backup_uses_rcs functionality has been removed from rc.subr.
 

share/mk/src.libnames.mk

@@ -490,8 +490,8 @@ LIBDIALOGDIR=	${OBJTOP}/gnu/lib/libdialog
 LIBGCOVDIR=	${OBJTOP}/gnu/lib/libgcov
 LIBGOMPDIR=	${OBJTOP}/gnu/lib/libgomp
 LIBGNUREGEXDIR=	${OBJTOP}/gnu/lib/libregex
-LIBSSPDIR=	${OBJTOP}/gnu/lib/libssp
-LIBSSP_NONSHAREDDIR=	${OBJTOP}/gnu/lib/libssp/libssp_nonshared
+LIBSSPDIR=	${OBJTOP}/lib/libssp
+LIBSSP_NONSHAREDDIR=	${OBJTOP}/lib/libssp/libssp_nonshared
 LIBSUPCPLUSPLUSDIR=	${OBJTOP}/gnu/lib/libsupc++
 LIBASN1DIR=	${OBJTOP}/kerberos5/lib/libasn1
 LIBGSSAPI_KRB5DIR=	${OBJTOP}/kerberos5/lib/libgssapi_krb5

share/mk/src.opts.mk

@@ -147,7 +147,6 @@ __DEFAULT_YES_OPTIONS = \
     RADIUS_SUPPORT \
     RCMDS \
     RBOOTD \
-    RCS \
     RESCUE \
     ROUTED \
     SENDMAIL \
@@ -187,6 +186,7 @@ __DEFAULT_NO_OPTIONS = \
     NAND \
     OFED \
     OPENLDAP \
+    RCS \
     SHARED_TOOLCHAIN \
     SORT_THREADS \
     SVN \

tools/build/options/WITHOUT_RCS

@@ -1,5 +0,0 @@
-.\" $FreeBSD$
-Set to not build
-.Xr rcs 1 ,
-.Xr etcupdate 8 ,
-and related utilities.

tools/build/options/WITH_RCS

@@ -0,0 +1,4 @@
+.\" $FreeBSD$
+Set to build
+.Xr rcs 1
+and related utilities.