Make canonicalization non sensitive to struct-ness of subtypes

Make canonicalization non sensitive to struct-ness of subtypes

In a previous patch, we made canonicalization independant from
struct-ness of class types.  This was in this commit:

    0e3416e Bug 19023 - Type canonicalization is sensitive to struct-ness

But then, that didn't handle the case of composite types which have a
subtype of class type T, where the same T was declared as "struct" and
as "class" in the same binary.

This patch handles that case by passing a flag to the functions that
build the pretty representation of types.  Note that the pretty
representation is used as a key in the hash map that contains
canonical types.  That flag is passed all the way down to the function
that builds the pretty representation for class types, which decides
to use either "struct" or "class" as a previx for the representation.

The type canonicalization code then passes that flag (properly set) to
the pretty representation function.

	* include/abg-fwd.h (get_type_name, get_function_type_name)
	(get_method_type_name, get_pretty_representation): Add an
	"internal" flag to all overoads.
	* include/abg-ir.h
	({type_or_decl_base, decl_base, type_decl, scope_type_decl,
	qualified_type_def, array_type_def, enum_type_decl, typedef_decl,
	var_decl, function_decl, function_decl::parameter, function_type,
	method_type, class_decl}::get_pretty_representation): Add an
	'internal' flag.
	({decl_base, qualified_type_def, pointer_type_def,
	reference_type_def, array_type_def, enum_type_decl::enumerator,
	function_decl::parameter}::get_qualified_name): Likewise.
	(qualified_type_def::build_name): Likewise.
	* src/abg-ir.cc ({decl_base, qualified_type_def, pointer_type_def,
	reference_type_def, array_type_def, enum_type_decl,
	enum_type_decl::enumerator,
	function_decl::parameter}::get_qualified_name): Take an "internal"
	flag.
	(qualified_type_def::build_name): Likewise.
	({decl_base, type_decl, namespace_decl, array_type_def,
	enum_type_decl, typedef_decl, var_decl, function_type,
	method_type, function_decl,
	class_decl}::get_pretty_representation): Likewise.
	(get_type_name, get_function_type_name, get_method_type_name)
	(get_pretty_representation): Likewise.
	(type_base::get_canonical_type_for): Call
	get_pretty_representation() with the "internal" flag set to
	"true", to get a pretty representation that is independant from
	the struct-ness of the subtypes of the type being canonicalized.

Signed-off-by: Dodji Seketeli <dodji@redhat.com>