Add an explicit note about the search path used by dlopen(3).

libexec/ld.elf_so/ld.elf_so.1

@@ -1,4 +1,4 @@
-.\"	$NetBSD: ld.elf_so.1,v 1.15 2010/12/17 08:50:26 wiz Exp $
+.\"	$NetBSD: ld.elf_so.1,v 1.16 2015/07/03 10:19:29 joerg Exp $
 .\"
 .\" Copyright (c) 2001 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -89,6 +89,11 @@ The list of default paths which is set to
 .Pa /usr/lib .
 .El
 .Pp
+Dynamic loading via
+.Xr dlopen 3
+uses the DT_RPATH entries of the main binary, independently of which object
+the call came from.
+.Pp
 .Nm
 will expand the following variables if present in the paths:
 .Bl -tag -width $PLATFORM