build world without INET6

[Дейтер Александр Ва]

Hello!

Why some components of the base system are compiled with -DINET6 despite 
of NOINET6=true in my /etc/make.conf?

For example:
kerberos5/Makefile.inc:CFLAGS+=-DINET6
lib/libc/net/Makefile.inc:CFLAGS+=-DINET6
lib/libfetch/Makefile:CFLAGS+=-DINET6
lib/libftpio/Makefile:CFLAGS+=-DINET6
lib/libutil/Makefile:CFLAGS+=-DINET6
libexec/ftpd/Makefile:CFLAGS+=-DINET6
libexec/rlogind/Makefile:CFLAGS+= -Wall -DINET6
libexec/telnetd/Makefile: -I${TELNETDIR} -DINET6
sbin/ifconfig/Makefile:CFLAGS+=-DINET6
sbin/route/Makefile:CFLAGS+=-DINET6
sbin/rtsol/Makefile:CFLAGS+=-DINET6
sys/modules/netgraph/fec/Makefile:CFLAGS += -DINET -DINET6
usr.bin/ftp/Makefile:CFLAGS+=-I${.CURDIR} -I${LUKEMFTP} -DINET6
usr.bin/logger/Makefile:CFLAGS+=-DINET6
usr.bin/netstat/Makefile:CFLAGS+=-DINET6
usr.bin/rpcinfo/Makefile:CFLAGS+=-DINET6
usr.bin/systat/Makefile:CFLAGS+=-DINET6
usr.bin/telnet/Makefile:CFLAGS+= -DINET6 -DIPSEC
usr.sbin/inetd/Makefile:CFLAGS+= -DINET6 -DIPSEC
usr.sbin/lpr/Makefile.inc:CFLAGS+= -DINET6
usr.sbin/ndp/Makefile:CFLAGS+= -DINET6
usr.sbin/rpcbind/Makefile:CFLAGS+= -DINET6
usr.sbin/rrenumd/Makefile:CFLAGS+= -DINET6
usr.sbin/rtadvd/Makefile:CFLAGS+= -DINET6
usr.sbin/rtsold/Makefile:CFLAGS+= -DINET6
usr.sbin/setkey/Makefile:CFLAGS+= -DIPSEC_DEBUG -DINET6
usr.sbin/syslogd/Makefile:CFLAGS+=-DINET6
usr.sbin/trpt/Makefile:CFLAGS+= -DINET6

It is possible to use macro, for example, as in lib/libpcap/Makefile?:

.if !defined(NOINET6)
CFLAGS+=-DINET6
.endif

Thanks a lot!