[regression] maven2.1 fails with cyclic dependency in case of extension/dependency for report-plugin to reactor-project

In my project (https://m-m-m.svn.sourceforge.net/svnroot/m-m-m/trunk/)
I am doing exactly what maven-checkstyle-plugin suggests as best practice for multi-module-builds:
http://maven.apache.org/plugins/maven-checkstyle-plugin/examples/multi-module-config.html

Howerver when I upgrade to maven 2.1 my build does not work anymore, while maven 2.0.10 works fine:

[INFO] The projects in the reactor contain a cyclic reference: Edge between 'Vertex

' and 'Vertex

' introduces to cycle in the graph net.s
f.m-m-m:mmm-setup --> net.sf.m-m-m:mmm-setup

Indeed the module mmm-setup inherits from the toplevel-pom and therefore has a maven-checkstyle-plugin
with a dependency on itself. However this worked with maven 2.0.x and if this is NOT going to be
"fixed" in 2.1, you need to supply an acceptable workaround and update instructions such as
the one linked above. Please also note that such config-moudles (net.sf.m-m-m:mmm-setup or
com.example.whizbang:build-tools) should typically be available in IDE and other modules might
depend on them so they have to be part of the reactor for eclipse:eclipse.