[regression] Build extensions are invisible to plugins in multi module build

[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO] 
[INFO] XWiki Platform - Tools - Archetype POM ............ SUCCESS [11.440s]
[INFO] XWiki Platform - Tools - XWiki Rendering Macro Archetype  FAILURE [5.984s]
[INFO] XWiki Platform - Tools - XWiki Component Archetype  SKIPPED
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 20.136s
[INFO] Finished at: Thu Jan 13 08:40:35 CET 2011
[INFO] Final Memory: 15M/81M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.codehaus.mojo:clirr-maven-plugin:2.2.3:check (clirr-check) on project xwiki-archetype-macro: Error finding previous version: Could not find artifact org.xwiki.platform.tools:xwiki-archetype-macro:maven-archetype:1.1 in xwiki-externals (http://maven.xwiki.org/externals)
[ERROR] 
[ERROR] Try downloading the file manually from the project website.
[ERROR] 
[ERROR] Then, install it using the command:
[ERROR] mvn install:install-file -DgroupId=org.xwiki.platform.tools -DartifactId=xwiki-archetype-macro -Dversion=1.1 -Dpackaging=maven-archetype -Dfile=/path/to/file
[ERROR] 
[ERROR] Alternatively, if you host your own repository you can deploy the file there:
[ERROR] mvn deploy:deploy-file -DgroupId=org.xwiki.platform.tools -DartifactId=xwiki-archetype-macro -Dversion=1.1 -Dpackaging=maven-archetype -Dfile=/path/to/file -Durl=[url] -DrepositoryId=[id]
[ERROR] 
[ERROR] 
[ERROR] org.xwiki.platform.tools:xwiki-archetype-macro:maven-archetype:1.1
[ERROR] 
[ERROR] from the specified remote repositories:
[ERROR] xwiki-externals (http://maven.xwiki.org/externals, releases=true, snapshots=true),
[ERROR] xwiki-releases (http://maven.xwiki.org/releases, releases=true, snapshots=false),
[ERROR] xwiki-snapshots (http://maven.xwiki.org/snapshots, releases=false, snapshots=true),
[ERROR] central (http://repo1.maven.org/maven2, releases=true, snapshots=false)
[ERROR] -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException
[ERROR] 
[ERROR] After correcting the problems, you can resume the build with the command
[ERROR]   mvn <goals> -rf :xwiki-archetype-macro