machinarium: move msg structure into separate file

src/mm_msg.h

@@ -0,0 +1,19 @@
+#ifndef MM_MSG_H_
+#define MM_MSG_H_
+
+/*
+ * machinarium.
+ *
+ * cooperative multitasking engine.
+*/
+
+typedef struct mm_msg_t mm_msg_t;
+
+struct mm_msg_t {
+	uint16_t  refs;
+	int       type;
+	void     *data;
+	mm_list_t link;
+};
+
+#endif

src/mm_msg_pool.h

@@ -7,16 +7,8 @@
  * cooperative multitasking engine.
 */
 
-typedef struct mm_msg_t     mm_msg_t;
 typedef struct mm_msgpool_t mm_msgpool_t;
 
-struct mm_msg_t {
-	uint16_t  refs;
-	int       type;
-	void     *data;
-	mm_list_t link;
-};
-
 struct mm_msgpool_t {
 	pthread_spinlock_t lock;
 	mm_list_t          list;