... It ended up not used, and long ago superseded by other TrackPanel
reorganization.
Such things as that (and many more) will be implemented with different
idioms (registries in various higher level code) without requiring changes in
this low level protocol for loading modules.
It was defined as taking a size_t paramater when it was written,
so the declarations used to call it should also use a size_t parameter
to ensure the call is correct.
FileDialog goes into audacity/src/widgets and the mod-* directories go into
audacity/modules.
This leaves nothing in lib-src that isn't a 3rd-party libs or supporting
files.
