cmRtSys.h/c: cmRtSysCtx.h now have cmTimeSpec_t timestamps.

These timestamps are set in _cmRtDspExecCallback() by cmApBufGetIO().
_cmRtSysEnable() now calls cmApBufOnPortEnable() to allow cmApBuf to be
aware of the audio stream starting and stopping.

cmRtSys.c

 #include "cmCtx.h"
 #include "cmMem.h"
 #include "cmMallocDebug.h"
+#include "cmTime.h"
 #include "cmAudioPort.h"
 #include "cmAudioNrtDev.h"
 #include "cmAudioPortFile.h"
   //   1) Buffers associated with disabled input/output channels will be set to NULL in iChArray[]/oChArray[].
   //   2) Buffers associated with channels marked for pass-through will be set to NULL in oChArray[].
   //   3) All samples returned in oChArray[] buffers will be set to zero.
-  cmApBufGetIO(cp->ss.args.inDevIdx, cp->ctx.iChArray, cp->ctx.iChCnt, cp->ss.args.outDevIdx, cp->ctx.oChArray, cp->ctx.oChCnt  );
+  cmApBufGetIO(cp->ss.args.inDevIdx,  cp->ctx.iChArray, cp->ctx.iChCnt, &cp->ctx.iTimeStamp, 
+               cp->ss.args.outDevIdx, cp->ctx.oChArray, cp->ctx.oChCnt, &cp->ctx.oTimeStamp  );
 
 
   // calling this function results in callbacks to _cmRtSysNetRecv()
   {
     _cmRtCfg_t* cp = p->ssArray + i;
 
+    cmApBufOnPortEnable(cp->ss.args.inDevIdx,enableFl);
+    cmApBufOnPortEnable(cp->ss.args.outDevIdx,enableFl);
+
     if( enableFl )
     {
       cp->cmdId = kNoCmdId;

cmRtSys.h

                                        // output (playback) buffers
     cmSample_t**        oChArray;      // each ele is a ptr to buffer with cfg.dspFramesPerCycle samples
     unsigned            oChCnt;        // count of output channels (ele's in oChArray[])
-
+    cmTimeSpec_t        oTimeStamp;
                                        // input (recording) buffers
     cmSample_t**        iChArray;      // each ele is a ptr to buffer with cfg.dspFramesPerCycle samples
     unsigned            iChCnt;        // count of input channels (ele's in iChArray[])
+    cmTimeSpec_t        iTimeStamp;          
     
   } cmRtSysCtx_t;