analyzer: add logging of aliasing
gcc/analyzer/ChangeLog:
* engine.cc (impl_run_checkers): Pass logger to engine ctor.
* region-model-manager.cc
(region_model_manager::region_model_manager): Add logger param and
use it to initialize m_logger.
* region-model.cc (engine::engine): New.
* region-model.h (region_model_manager::region_model_manager):
Add logger param.
(region_model_manager::get_logger): New.
(region_model_manager::m_logger): New field.
(engine::engine): New.
* store.cc (store_manager::get_logger): New.
(store::set_value): Log scope. Log when marking a cluster as
unknown due to possible aliasing.
* store.h (store_manager::get_logger): New decl.