Generate correct fn specs for some Fortran library functions.

Generate correct fn specs for some Fortran library functions.

This patch works by generating the correct fn spec from the
actual arguments in specific_intrinsic_symbol, and by passing this
down via gfc_get_extern_function_decl to gfc_get_function_type.
CSHIFT remains to be done.

gcc/fortran/ChangeLog:

	PR fortran/97454
	* trans-decl.c (gfc_get_extern_function_decl): Add argument
	fnspec.
	* trans-intrinsic.c (MAX_SPEC_ARG): Define.
	(intrinsic_fnspec): New function.
	(ADD_CHAR): Define.
	(specific_intrinsic_symbol): Adjust comment. Pass
	fn spec to gfc_get_extern_function_decl.
	(gfc_conv_intrinsic_funcall): Add ANY, ALL, NORM2, PRODUCT
	and SUM intrnisic. Add FIXME for cshift et al.
	* trans-types.c	(gfc_get_function_type): Add fnspec argument,
	handle it.
	* trans-types.h (gfc_get_function_type): Add optinal fnspec
	argument.
	* trans.h (gfc_get_extern_function_decl): Likewise.