document fix for PR 49587

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@986729 13f79535-47bb-0310-9956-ffa450edef68

WHATSNEW

@@ -127,6 +127,11 @@ Fixed bugs:
    for a bunch of characters, then stealing them from a following <input>.
    Bugzilla Report 49119.
 
+ * Ant could be leaking threads for each forked process (started by
+   <exec>, <apply>, <java> or similar tasks) that didn't receive input
+   from a resource or string explicitly.
+   Bugzilla Report 49587.
+
 Other changes:
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