Hide structure definition from public interface, as it is incompatible with ARC

ChangeLog

@@ -1,3 +1,10 @@
+2019-07-14  Wolfgang Lux  <wolfgang.lux@gmail.com>
+
+	* SQLClient.h
+	* SQLClientPool.m:
+	Hide definition of SQLClientPoolItem from the public interface,
+	as it is incompatible with automatic reference counting.
+
 2019-05-03  Wolfgang Lux  <wolfgang.lux@gmail.com>
 
 	* SQLClient.m:

SQLClient.h

@@ -1681,12 +1681,7 @@ SQLCLIENT_PRIVATE
 - (void) setCacheThread: (NSThread*)aThread;
 @end
 
-typedef struct {
-    SQLClient           *c;     /** The clients of the pool. */
-    NSThread            *o;     /** The thread owning the client */
-    NSUInteger          u;      /** Count of client usage. */
-    NSTimeInterval      t;      /** When client was removed from pool. */
-} SQLClientPoolItem;
+typedef struct _SQLClientPoolItem SQLClientPoolItem;
 
 /** <p>An SQLClientPool instance may be used to create/control a pool of
  * client objects.  Code may obtain autoreleased proxies to the clients

SQLClientPool.m

@@ -39,6 +39,13 @@
 #import	<Performance/GSCache.h>
 #import	"SQLClient.h"
 
+struct _SQLClientPoolItem {
+    SQLClient           *c;     /** The clients of the pool. */
+    NSThread            *o;     /** The thread owning the client */
+    NSUInteger          u;      /** Count of client usage. */
+    NSTimeInterval      t;      /** When client was removed from pool. */
+};
+
 @interface      SQLClient(Pool)
 - (void) _clearPool: (SQLClientPool*)p;
 @end