Add build opton MK_LS_COLORS to control whether ls(1) supports colors

(and thus needs to depend on libtermcap). Embedded systems may not
want or need colors.

Obtained from:	Juniper Networks, Inc.

bin/ls/Makefile

@@ -1,12 +1,15 @@
 #	@(#)Makefile	8.1 (Berkeley) 6/2/93
 # $FreeBSD$
 
+.include <bsd.own.mk>
+
 PROG=	ls
 SRCS=	cmp.c ls.c print.c util.c
 DPADD=	${LIBUTIL}
 LDADD=	-lutil
 
-.if !defined(RELEASE_CRUNCH)
+.if !defined(RELEASE_CRUNCH) && \
+	${MK_LS_COLORS} != no
 CFLAGS+= -DCOLORLS
 DPADD+=	${LIBTERMCAP}
 LDADD+=	-ltermcap

share/mk/bsd.own.mk

@@ -367,6 +367,7 @@ __DEFAULT_YES_OPTIONS = \
     LOCALES \
     LOCATE \
     LPR \
+    LS_COLORS \
     MAIL \
     MAILWRAPPER \
     MAKE \