use new comms_ackAny() call to send ACKs at points where currently

resendAll is being called.  Dramatically reduces SMS message count
when app is being relaunched and backgrounded between turns.

xwords4/android/XWords4-sms/jni/Android.mk

@@ -15,6 +15,7 @@ local_DEFINES += \
 	$(local_DEBUG) \
 	-DXWFEATURE_RELAY \
 	-DXWFEATURE_SMS \
+	-DXWFEATURE_COMMSACK \
 	-DXWFEATURE_TURNCHANGENOTIFY \
 	-DXWFEATURE_CHAT \
 	-DCOMMS_XPORT_FLAGSPROC \

xwords4/android/XWords4/jni/Android.mk

@@ -14,6 +14,7 @@ local_LDLIBS += -llog
 local_DEFINES += \
 	$(local_DEBUG) \
 	-DXWFEATURE_RELAY \
+	-DXWFEATURE_COMMSACK \
 	-DXWFEATURE_TURNCHANGENOTIFY \
 	-DXWFEATURE_CHAT \
 	-DCOMMS_XPORT_FLAGSPROC \

xwords4/android/XWords4/jni/xwjni.c

@@ -1267,6 +1267,18 @@ Java_org_eehouse_android_xw4_jni_XwJNI_comms_1resendAll
     XWJNI_END();
 }
 
+#ifdef XWFEATURE_COMMSACK
+JNIEXPORT void JNICALL
+Java_org_eehouse_android_xw4_jni_XwJNI_comms_1ackAny
+( JNIEnv* env, jclass C, jint gamePtr )
+{
+    XWJNI_START();
+    XP_ASSERT( !!state->game.comms );
+    (void)comms_ackAny( state->game.comms );
+    XWJNI_END();
+}
+#endif
+
 JNIEXPORT void JNICALL
 Java_org_eehouse_android_xw4_jni_XwJNI_comms_1transportFailed
 ( JNIEnv* env, jclass C, jint gamePtr )

xwords4/android/XWords4/src/org/eehouse/android/xw4/CommsTransport.java

@@ -224,7 +224,7 @@ public class CommsTransport implements TransportProcs,
 
     public void tickle()
     {
-        m_jniThread.handle( JNIThread.JNICmd.CMD_RESEND );
+        m_jniThread.handle( JNIThread.JNICmd.CMD_RESEND_ACK );
         // CommsAddrRec addr = new CommsAddrRec( m_context );
         // XwJNI.comms_getAddr( m_jniGamePtr, addr );
         // switch( addr.conType ) {

xwords4/android/XWords4/src/org/eehouse/android/xw4/GameUtils.java

@@ -679,6 +679,7 @@ public class GameUtils {
                         || draw;
                 }
             }
+            XwJNI.comms_ackAny( gamePtr );
 
             // update gi to reflect changes due to messages
             XwJNI.game_getGi( gamePtr, gi );

xwords4/android/XWords4/src/org/eehouse/android/xw4/jni/JNIThread.java

@@ -76,6 +76,7 @@ public class JNIThread extends Thread {
             CMD_COUNTS_VALUES,
             CMD_REMAINING,
             CMD_RESEND,
+            CMD_RESEND_ACK,
             CMD_HISTORY,
             CMD_FINAL,
             CMD_ENDGAME,
@@ -480,6 +481,10 @@ public class JNIThread extends Thread {
             case CMD_RESEND:
                 XwJNI.comms_resendAll( m_jniGamePtr );
                 break;
+            case CMD_RESEND_ACK:
+                XwJNI.comms_resendAll( m_jniGamePtr );
+                XwJNI.comms_ackAny( m_jniGamePtr );
+                break;
 
             case CMD_HISTORY:
                 boolean gameOver = XwJNI.server_getGameIsOver( m_jniGamePtr );

xwords4/android/XWords4/src/org/eehouse/android/xw4/jni/XwJNI.java

@@ -230,6 +230,7 @@ public class XwJNI {
     public static native void comms_getAddr( int gamePtr, CommsAddrRec addr );
     public static native void comms_setAddr( int gamePtr, CommsAddrRec addr );
     public static native void comms_resendAll( int gamePtr );
+    public static native void comms_ackAny( int gamePtr );
     public static native void comms_transportFailed( int gamePtr );
     public static native boolean comms_isConnected( int gamePtr );