WIP: Add libgstplugins.so containing all static plugins
When building with -Ddefault_library=static, also build a single library containing all built plugins. Any external dependencies are still dynamically linked.
A monolithic library is easier to distribute, and in some envs like Android is required.
- Fails to link when opus is built in both -bad and -base
- Fails to link with x264 is enabled because it's missing fPIC
- When using --wrap-mode forcefallback it both static and dynamic link to glib. Probably somewhere a subproject is missing fallback to glib subproject.
- Include glib-networking modules
- Generate a function that register all static plugins