When attaching to a process and doing a backtrace, the following
assertion failure occurs:

internal-error: make_cv_type: Assertion `TYPE_OBJFILE (*typeptr) ==
TYPE_OBJFILE (type) || TYPE_STUB (*typeptr)' failed.

This is due to code in gdbtypes.c:check_typedef:

  /* If this is a struct/class/union with no fields, then check whether a
     full definition exists somewhere else.  This is for systems where a
     type definition with no fields is issued for such types, instead of
     identifying them as stub types in the first place */

  if (TYPE_IS_OPAQUE (type) && opaque_type_resolution &&
!currently_reading_symtab)
    {
      char *name = type_name_no_tag (type);
      struct type *newtype;
      if (name == NULL)
        {
          stub_noname_complaint ();           return type;
        }
      newtype = lookup_transparent_type (name);
      if (newtype)
        make_cv_type (is_const, is_volatile, newtype, &type);
    }

What's happening is the type returned by lookup_transparent_type is
from a shared library that the process loads, but the original
incomplete type reference is from the application binary. So the
objfile entries in the types differ, causing the assertion failure of
TYPE_OBJFILE (*typeptr) == TYPE_OBJFILE (type).

I can workaround this with the attached patch, but I'm not sure it's
the right thing. This just forces the type to be treated as a STUB.