Mention that ldconfig is a.out only.

Should fix PR bin/10299.

sbin/ldconfig/ldconfig.8

@@ -1,4 +1,4 @@
-.\"	$NetBSD: ldconfig.8,v 1.10 1999/02/22 23:07:16 msaitoh Exp $
+.\"	$NetBSD: ldconfig.8,v 1.11 2000/10/08 09:33:13 bjh21 Exp $
 .\"
 .\" Copyright (c) 1998 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -34,12 +34,12 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd August 24, 1997
+.Dd October 8, 2000
 .Dt LDCONFIG 8
 .Os NetBSD
 .Sh NAME
 .Nm ldconfig
-.Nd configure the shared library cache
+.Nd configure the a.out shared library cache
 .Sh SYNOPSIS
 .Nm ldconfig
 .Op Fl cmrsSv
@@ -48,10 +48,18 @@
 .Nm
 is used to prepare a set of
 .Dq hints
-for use by the run-time linker
+for use by the a.out run-time linker
 .Nm ld.so
 to facilitate quick lookup of shared libraries available in multiple
-directories.  By default, it scans a set of built-in system directories,
+directories.
+.Nm
+is only available on systems that use the
+.Dq a.out
+format for executables and libraries \(en on ELF systems, all the work
+is done by
+.Nm ld.elf_so .
+.Pp
+By default, it scans a set of built-in system directories,
 directories listed in
 .Pa /etc/ld.so.conf ,
 and any