Add support for inetd RFC862 echo server

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

plugins/Makefile.am

@@ -16,6 +16,10 @@ if BUILD_DBUS_PLUGIN
 libplug_la_SOURCES += dbus.c
 endif
 
+if BUILD_INETD_ECHO_PLUGIN
+libplug_la_SOURCES += echo.c
+endif
+
 if BUILD_LOST_PLUGIN
 libplug_la_SOURCES += lost.c
 endif
@@ -36,6 +40,10 @@ if BUILD_DBUS_PLUGIN
 pkglib_LTLIBRARIES += dbus.la
 endif
 
+if BUILD_INETD_ECHO_PLUGIN
+pkglib_LTLIBRARIES += echo.la
+endif
+
 if BUILD_LOST_PLUGIN
 pkglib_LTLIBRARIES += lost.la
 endif