include: improve compatibility with C++ apps.

This patch lets a C++ application use more of Zephyr by adding guards
and changeing some constructs to the C++11 equivalent.

Changes include:

- Adding guards
- Switching to static_assert
- Switching to a template for ARRAY_SIZE as g++ doesn't have the
  builtin.
- Re-ordering designated initialisers to match the struct field order
  as G++ only supports simple designated initialisers.

Signed-off-by: Michael Hope <mlhx@google.com>

include/kernel.h

@@ -1549,8 +1549,8 @@ struct k_queue {
 
 #define _K_QUEUE_INITIALIZER(obj) \
 	{ \
-	.wait_q = SYS_DLIST_STATIC_INIT(&obj.wait_q), \
 	.data_q = SYS_SLIST_STATIC_INIT(&obj.data_q), \
+	.wait_q = SYS_DLIST_STATIC_INIT(&obj.wait_q), \
 	_POLL_EVENT_OBJ_INIT(obj) \
 	_OBJECT_TRACING_INIT \
 	}