Добавить поддержку Fossil (fossil-scm.org) в TeamCity через Java-плагин и JNI с libfossil.

Документация по плагинам:
https://plugins.jetbrains.com/docs/teamcity/versio...

Плагин для Git для примера:
https://github.com/JetBrains/teamcity-git

libfossil (JNI нет, нужно написать):
https://fossil.wanderinghorse.net/r/libfossil

Из документации (нужно всё, включая опциональные части и checkout на агенте):

The server-side part of a VCS plugin is responsible the following major operations:

• collecting changes between versions
• building of a patch from version to version
• getting content of a file (for web diff, duplicates finder, and some other places)

There are also optional parts:

• labeling / tagging
• personal builds, which require corresponding support in IDE. This dependency may be eliminated in the future.

The agent-side part is optional and only responsible for checking out and updating project sources on agents. In contrast to server-side checkout it offers a traditional approach to interacting between a CI system and VCS – when source code is checked out into the same location where it's built.