compinit in emulation

[Bart Schaefer <schaefer@xxxxxxxxxxxxxxxx>]

The documentation says:
  If the parameter _compdir is set, compinit uses it as a directory where
  completion functions can be found; this is only necessary if they are
  not already in the function search path.

However, this depends on the fpath/FPATH tied variable linkage, which
is disabled when not in native zsh mode.  I wrongly expected 'emulate
-R zsh' to fix this, and spent quite a while down a rabbit hole trying
to figure out what was wrong.

Obviously we've been getting by with this for the past couple of
decades, but:  Does anyone think this should be repaired?