Ahaggar: add the TYPE_DECL walker

Signed-off-by: Djalal Harouni <tixxdz@opendz.org>
Ahaggar: regroup *_DECL nodes

Signed-off-by: Djalal Harouni <tixxdz@opendz.org>
Ahaggar: add the LABEL_DECL node walker

Signed-off-by: Djalal Harouni <tixxdz@opendz.org>
Ahaggar: walk LABEL_DECL nodes

Signed-off-by: Djalal Harouni <tixxdz@opendz.org>
Ahaggar: regroup more *_EXPR nodes

Signed-off-by: Djalal Harouni <tixxdz@opendz.org>