- Hook up BSD sort to the build. By default, it will be installed as

"bsdsort" and GNU sort will be the default "sort".  When WITH_BSD_SORT
  is set, BSD sort will be the default "sort" and GNU sort will be installed
  as "gnusort".

gnu/usr.bin/sort/Makefile

@@ -3,7 +3,18 @@
 SORTDIR= ${.CURDIR}/../../../contrib/gnu-sort
 .PATH: ${SORTDIR}/lib ${SORTDIR}/src ${SORTDIR}/man
 
+.include <bsd.own.mk>
+
+.if ${MK_BSD_SORT} != "yes"
 PROG=	sort
+.else
+PROG=	gnusort
+
+CLEANFILES+= gnusort.1
+gnusort.1: sort.1
+	cp ${.ALLSRC} ${.TARGET}
+.endif
+
 SRCS=   sort.c \
 	__fpending.c \
 	argmatch.c \

share/mk/bsd.own.mk

@@ -413,6 +413,7 @@ __DEFAULT_YES_OPTIONS = \
 
 __DEFAULT_NO_OPTIONS = \
     BSD_GREP \
+    BSD_SORT \
     BIND_IDN \
     BIND_LARGE_FILE \
     BIND_LIBS \

tools/build/options/WITH_BSD_SORT

@@ -0,0 +1,2 @@
+.\" $FreeBSD$
+Install BSD-licensed sort as 'sort' instead of GNU sort.

usr.bin/Makefile

@@ -141,6 +141,7 @@ SUBDIR=	alias \
 	shar \
 	showmount \
 	sockstat \
+	sort \
 	split \
 	stat \
 	stdbuf \