417262: add build time dependency on com.sun.syndication

Change-Id: I7776834cff563eb40edfe93c888dce9e88d957c5
Task-Url: https://bugs.eclipse.org/bugs/show_bug.cgi?id=417262
diff --git a/org.eclipse.mylyn.commons.notifications.feed/plugin.properties b/org.eclipse.mylyn.commons.notifications.feed/plugin.properties
index 9d7af38..90d9add 100644
--- a/org.eclipse.mylyn.commons.notifications.feed/plugin.properties
+++ b/org.eclipse.mylyn.commons.notifications.feed/plugin.properties
@@ -11,3 +11,5 @@
 
 Bundle-Vendor = Eclipse Mylyn
 Bundle-Name = Mylyn Commons
+
+jars.extra.classpath = platform:/plugin/com.sun.syndication