PR21730 - would anybody shed a tear for symbol.c(check_done)?

["Paul Richard Thomas" <paul dot richard dot thomas at gmail dot com>]

As far as I can tell, the only purpose of the above function is to
cause PR21730; it also caused PR20869 but that was fixed otherwise.

The comment above it reads:

/* Used to prevent changing the attributes of a symbol after it has been
  used.  This check is only done for dummy variables as only these can be
  used in specification expressions.  Applying this to all symbols causes
  an error when we reach the body of a contained function.  */

and it produces the error

 gfc_error ("Cannot change attributes of symbol at %L"
            " after it has been used", where);

Other errors come up in all the circumstances that I have tried, where
it might have been triggered.  I note that it has gone from g95.

Trunk with it reduced to do nothing but return 0 regtests on
PIV/Cygwin_NT - OK for trunk to remove it and all references to it,
with an appropriate ChangeLog?

Paul