Allow CFI_cdesc_t in argument lists with -fc-prototypes.

Allow CFI_cdesc_t in argument lists with -fc-prototypes.

This patch fixes and reorganizes dumping C prototypes.  It makes the following
changes:

	- BIND(C) types are now always output before any global symbols
	- CFI_cdesc_t is issued for assumed shape and assumed rank arguments.
	- BIND(C,NAME="...") entities were not always issued.

gcc/fortran/ChangeLog:

	PR fortran/118359
	* dump-parse-tree.cc (show_external_symbol): New function.
	(write_type): Add prototype, put in restrictions on what not to dump.
	(has_cfi_cdesc): New function.
	(need_iso_fortran_binding): New function.
	(gfc_dump_c_prototypes): Adjust to take only a file output.  Add
	"#include <ISO_Fortran_binding.h" if CFI_cdesc_t is found.
	Traverse global namespaces to dump types and the globalsymol list
	to dump external symbols.
	(gfc_dump_external_c_prototypes): Traverse global namespaces.
	(get_c_type_name): Handle CFI_cdesc_t.
	(write_proc): Also pass array spec to get_c_type_name.
	* gfortran.h (gfc_dump_c_prototypes): Adjust prototype.
	* parse.cc (gfc_parse_file): Adjust call to gfc_dump_c_prototypes.