capgen Fortran parser does not accept internal DDTs as part of a registered DDT

Description

Error:

Reading host model data from /path/to/mod_mytype.meta
table: 'linterp_table_t' is not a valid derived Fortran type, at /path/to/mod_mytype.meta:33
'
CMake Error at external/ccpp/CMakeLists.txt:135 (message):
  ccpp_capgen.py FAILED: result = 1

-- Configuring incomplete, errors occurred!

Fortran:

  !> Corresponding derived type mytype_dat_t
  !! \section arg_table_mytype_dat_t Argument Table
  !! \htmlinclude mytype_dat_t.html
  !!
  type mytype_dat_t
    type(linterp_table_t) :: table
...

Metadata:

[ccpp-table-properties]
  name = mytype_dat_t
  type = ddt
  dependencies = ../ccpp-physics/physics/tools/mpiutil.F90,mod_utils.F90
  module_name = mod_mytype

[ccpp-arg-table]
  name = mytype_dat_t
  type = ddt

The type linterp_table_t is defined in the dependency mod_utils.F90 and is nowhere exposed in the metadata. Capgen shouldn't care. All it needs to know is how to access mytype_dat_t and what dependencies to compile.

Steps to Reproduce

See above. Should be reproducible with any of the capgen unit tests from develop

Additional Context

n/a

Output

See above

Start with ccpp_capgen.py and the capgen unit tests referenced in the issue, then inspect the failure reported through external/ccpp/CMakeLists.txt:135. Reproduce the case where mytype_dat_t contains linterp_table_t from mod_utils.F90. Done means capgen accepts the registered DDT without metadata for the internal type while retaining the listed dependency handling.