Feature Proposal: source-submodules option

Rationale

Some projects(like Poedit) includes many submodules that aren’t needed in building on GNU+Linux platform, we should have a way to exclude fetching them in the snapcraft.yaml.

Problems to Solve

Proposal

This proposal requests a new source-submodules option which accepts a list of submodule paths for snapcraft to run git submodule init to initialize with, when this key existed the default behavior of initializing and updating all active submodules in .gitmodules shall be overrided.

Example Config

parts:
  poedit:
    plugin: autotools
    install-via: prefix
    source: https://github.com/vslavik/poedit.git
    source-submodules:
      - deps/wx
      - deps/json