* mangle.c (write_number): Take an unsigned HOST_WIDE_INT as an
	argument.
	(write_signed_number): New macro.
	(write_unsigned_number): Likewise.
	(write_source_name): Use them.
	(write_number): Handle signed and unsigned values.
	(write_integer_cst): Use tree_int_cst_sgn, and use
	write_unsigned_number or write_signed_number as appropriate.
	(write_discriminator): Use write_unsigned_number or
	write_signed_number as appropriate.
	(write_template_arg_literal): Likewise.
	(write_array_type): Use tree_low_cst.
	(write_template_parm):  Use write_unsigned_number or
	write_signed_number as appropriate.
	(write_substitution): Adjust call to write_number.
	(write_type): Get the TYPE_MAIN_VARIANT before mangling it.
	(write_expression): Handle non-type template arguments of
	reference type correctly.
	(mangle_thunk): Use write_signed_number.

	* mangle.c (find_substition): Don't mangle objects with typename
	substitutions (e.g. "cin" as "Si").

Co-Authored-By: Mark Mitchell <mark@codesourcery.com>

From-SVN: r34488