re PR debug/71906 (Fortran allocatable strings debug info type size regression)

re PR debug/71906 (Fortran allocatable strings debug info type size regression)

	PR debug/71906
	* dwarf2out.c (string_types): New variable.
	(gen_array_type_die): Change early_dwarf handling of
	DW_AT_string_length, create DW_OP_call4 referencing the
	length var temporarily.  Handle parameters that are pointers
	to string length.
	(adjust_string_types): New function.
	(gen_subprogram_die): Temporarily set string_types to local var,
	call adjust_string_types if needed.
	(non_dwarf_expression, copy_deref_exprloc, optimize_string_length):
	New functions.
	(resolve_addr): Adjust DW_AT_string_length if it is DW_OP_call4.

	* trans-decl.c (gfc_get_symbol_decl): Call gfc_finish_var_decl
	for decl's character length before gfc_finish_var_decl on the
	decl itself.

From-SVN: r239469