Merged Murali Shankar's iocLogPrefix changes.

Adjusted a few things during the merge.

documentation/RELEASE_NOTES.html

@@ -15,6 +15,16 @@ EPICS Base 3.15.0.x releases are not intended for use in production systems.</p>
 <h2 align="center">Changes between 3.14.x and 3.15.0.x</h2>
 <!-- Insert new items immediately below here ... -->
 
+<h3>
+Added support for iocLogPrefix</h3>
+
+<p>
+Added a <code>iocLogPrefix</code> command to <code>iocsh</code>. This adds a
+prefix to all messages from this IOC (or other log client) as they get sent to the
+iocLogServer. This lets sites use the "fac=&lt;<i>facility</i>&gt;" syntax for
+displaying the facility, process name etc. in log viewers like the
+<code>cmlogviewer<code>.</p>
+
 <h3>
 Reworked the epicsEvent C &amp; C++ APIs</h3>