Always install backward compatibility timezones, as they are installed

on all major Linux distributions as well as NetBSD and OpenBSD.

Remove the undocumented ZONEINFO_OLD_TIMEZONES_SUPPORT and the deprecated
OLDTIMEZONES knobs as they are now the default.

Reviewed by:		ngie, rgrimes
MFC after:		2 weeks
Differential Revision:	https://reviews.freebsd.org/D24306

etc/mtree/BSD.usr.dist

@@ -1253,16 +1253,26 @@
             ..
             Australia
             ..
+            Brazil
+            ..
+            Canada
+            ..
+            Chile
+            ..
             Etc
             ..
             Europe
             ..
             Indian
             ..
+            Mexico
+            ..
             Pacific
             ..
             SystemV
             ..
+            US
+            ..
         ..
     ..
     src             nochange

share/mk/src.opts.mk

@@ -218,7 +218,6 @@ __DEFAULT_NO_OPTIONS = \
     SORT_THREADS \
     SVN \
     ZONEINFO_LEAPSECONDS_SUPPORT \
-    ZONEINFO_OLD_TIMEZONES_SUPPORT \
 
 # LEFT/RIGHT. Left options which default to "yes" unless their corresponding
 # RIGHT option is disabled.
@@ -466,7 +465,6 @@ MK_GOOGLETEST:=	no
 
 .if ${MK_ZONEINFO} == "no"
 MK_ZONEINFO_LEAPSECONDS_SUPPORT:= no
-MK_ZONEINFO_OLD_TIMEZONES_SUPPORT:= no
 .endif
 
 .if ${MK_CROSS_COMPILER} == "no"

share/zoneinfo/Makefile

@@ -40,11 +40,6 @@ CONTRIBDIR=	${SRCTOP}/contrib/tzdata/
 MK_ZONEINFO_LEAPSECONDS_SUPPORT= yes
 .endif
 
-.if defined(OLDTIMEZONES)
-.warning "Using backwards compatibility variable for OLDTIMEZONES; please use WITH_ZONEINFO_OLD_TIMEZONES_SUPPORT instead"
-MK_ZONEINFO_OLD_TIMEZONES_SUPPORT= yes
-.endif
-
 .if ${MK_ZONEINFO_LEAPSECONDS_SUPPORT} != "no"
 LEAPFILE=	-L ${CONTRIBDIR}leapseconds
 .else
@@ -53,11 +48,8 @@ LEAPFILE=
 
 TZFILES=	africa antarctica asia australasia etcetera europe \
 		factory northamerica southamerica
-POSIXRULES=	America/New_York
-
-.if ${MK_ZONEINFO_OLD_TIMEZONES_SUPPORT} != "no"
 TZFILES+=	backward systemv
-.endif
+POSIXRULES=	America/New_York
 
 TZFILES:=	${TZFILES:S/^/${CONTRIBDIR}/}
 
@@ -78,10 +70,7 @@ TZBUILDSUBDIRS=	\
 		Indian \
 		Pacific \
 		SystemV
-
-.if ${MK_ZONEINFO_OLD_TIMEZONES_SUPPORT} != "no"
 TZBUILDSUBDIRS+= US Mexico Chile Canada Brazil
-.endif
 
 .if !defined(_SKIP_BUILD)
 all: zoneinfo

share/zoneinfo/tests/Makefile

@@ -8,10 +8,8 @@ PACKAGE=	tests
 
 FILESGROUPS+=	TESTFILES
 
-.if ${MK_ZONEINFO_OLD_TIMEZONES_SUPPORT} != "no"
 ATF_TESTS_SH+=	backward_test
 TESTFILES+=	backward
-.endif
 
 TESTFILES+=	zoneinfo_common.sh
 TESTFILESPACKAGE= ${PACKAGE}