Index: src/config.xml
===================================================================
--- src/config.xml.orig	2015-06-27 13:40:48.000000000 +0200
+++ src/config.xml	2015-10-05 15:50:05.584725277 +0200
@@ -3130,7 +3130,7 @@
 ]]>
       </docs>
     </option>
-    <option type='int' id='DOT_NUM_THREADS' defval='0' minval='0' maxval='32' depends='HAVE_DOT'>
+    <option type='int' id='DOT_NUM_THREADS' defval='1' minval='0' maxval='32' depends='HAVE_DOT'>
       <docs>
 <![CDATA[
  The \c DOT_NUM_THREADS specifies the number of \c dot invocations doxygen is