Add note warning that OS X updates usually overwrite /etc/rc.

diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml
index 1d251af2424c1d924f4a99b89920beca7c212727..7a70f07a4d378ed1f21b363558567573c139ddda 100644 (file)
--- a/doc/src/sgml/runtime.sgml
+++ b/doc/src/sgml/runtime.sgml
@@ -4427,7 +4427,9 @@ sysctl -w kern.sysv.shmseg
 sysctl -w kern.sysv.shmall
 </programlisting>
         In OS X 10.3, these commands have been moved to <filename>/etc/rc</>
-        and must be edited there.
+        and must be edited there.  Note that <filename>/etc/rc</> is usually
+        overwritten by OS X updates (such as 10.3.6 to 10.3.7) so you
+        should expect to have to redo your editing after each update.
        </para>
       </listitem>
      </varlistentry>