Couchbase project development is based around git source-control system and the higher-level repo tool.
All components for a couchbase build are defined by a repo manifest XML file.
The specific components depend on which version of Couchbase/Membase that you wish to build.
For example, Membase 1.8 is defined by membase/manifest/branch-1.8.xml, and Couchbase 2.0 is defined by membase/manifest/branch-2.0.xml.