Add include directive

chrony.texi

@@ -1179,6 +1179,7 @@ directives can occur in any order in the file.
 * dumpdir directive::           Specify directory for dumping measurements
 * dumponexit directive::        Dump measurements when daemon exits
 * fallbackdrift directive::     Specify fallback drift intervals
+* include directive::           Include a configuration file
 * initstepslew directive::      Trim the system clock on boot-up.
 * keyfile directive::           Specify location of file containing keys
 * linux_hz directive::          Define a non-standard value of the kernel HZ constant
@@ -1601,6 +1602,17 @@ By default (or if the specified maximum or minimum is 0), no fallbacks
 will be used and the clock frequency will stay at the last value
 calculated before synchronisation was lost.
 @c }}}
+@c {{{ include
+@node include directive
+@subsection include
+The @code{include} directive includes a specified configuration file.
+This is useful when maintaining configuration on multiple hosts to
+keep the differences in a separate file.
+
+@example
+include /etc/chrony/local.conf
+@end example
+@c }}}
 @c {{{ initstepslew
 @node initstepslew directive
 @subsection initstepslew