If you are looking to build WSO2 Carbon based products such as WSO2 ESB, Stratos, and the entire WSO2 Carbon platform, you have found the correct article. Just follow the below steps, to build the trunk.
Checkout orbit, kernel, and platform.
svn co https://svn.wso2.org/repos/wso2/carbon/orbit/trunk/ orbit
svn co https://svn.wso2.org/repos/wso2/carbon/kernel/trunk/ kernel
svn co https://svn.wso2.org/repos/wso2/carbon/platform/trunk/ platform
Build in the order (orbit -> kernel -> platform), using maven3.
mvn clean install