analyzer: start adding support for errno

analyzer: start adding support for errno

gcc/analyzer/ChangeLog:
	* region-model-impl-calls.cc
	(region_model::impl_call_errno_location): New.
	* region-model-manager.cc
	(region_model_manager::region_model_manager): Initialize
	m_thread_local_region and m_errno_region.
	* region-model-manager.h (region_model_manager::get_errno_region):
	New accessor.
	(region_model_manager::m_thread_local_region): New.
	(region_model_manager::m_errno_region): New.
	* region-model.cc (region_model::on_call_pre): Special-case
	"__errno_location".
	(region_model::set_errno): New.
	* region-model.h (impl_call_errno_location): New decl.
	(region_model::set_errno): New decl.
	* region.cc (thread_local_region::dump_to_pp): New.
	(errno_region::dump_to_pp): New.
	* region.h (enum memory_space): Add MEMSPACE_THREAD_LOCAL.
	(enum region_kind): Add RK_THREAD_LOCAL and RK_ERRNO.
	(class thread_local_region): New.
	(is_a_helper <const thread_local_region *>::test): New.
	(class errno_region): New.
	(is_a_helper <const errno_region *>::test): New.
	* store.cc (binding_cluster::escaped_p): New.
	(store::escaped_p): Treat errno as always having escaped.
	(store::replay_call_summary_cluster): Handle RK_THREAD_LOCAL and
	RK_ERRNO.
	* store.h (binding_cluster::escaped_p): Remove definition.

gcc/testsuite/ChangeLog:
	* gcc.dg/analyzer/errno-1.c: New test.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>