add some HISTORY about the inspiration for this command

usr.bin/getent/getent.1

@@ -1,4 +1,4 @@
-.\"	$NetBSD: getent.1,v 1.7 2004/11/29 04:13:15 lukem Exp $
+.\"	$NetBSD: getent.1,v 1.8 2004/12/03 23:05:32 lukem Exp $
 .\"
 .\" Copyright (c) 2004 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -34,7 +34,7 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd November 29, 2004
+.Dd December 3, 2004
 .Dt GETENT 1
 .Os
 .Sh NAME
@@ -112,3 +112,7 @@ A
 .Nm
 command appeared in
 .Nx 3.0 .
+It was based on the command of the same name in
+.Tn Solaris
+and
+.Tn Linux .