This is a workaround for a Meson bug that incorrectly trigger
reconfigure when files change in build directory. This commit can be
reverted once GStreamer depends on Meson >=0.54.0.
See https://github.com/mesonbuild/meson/pull/6770Fixes: #85
To build the documentation, we are maintaining a 'standardise' `plugins`
variable accross all modules to list all plugins and generate
documentation for them.
This is also used to get the right plugin path when inspecting plugins
for the documentation.
