Prepare to convert various types to size_t.

webrtc/modules/audio_coding/neteq/test/RTPencode.cc

Index: webrtc/modules/audio_coding/neteq/test/RTPencode.cc
diff --git a/webrtc/modules/audio_coding/neteq/test/RTPencode.cc b/webrtc/modules/audio_coding/neteq/test/RTPencode.cc
index 7d8d60de51a593e0587464b2589591cbceb69474..1ef9ce535ad70717b0c59626893ea01b528dd169 100644
--- a/webrtc/modules/audio_coding/neteq/test/RTPencode.cc
+++ b/webrtc/modules/audio_coding/neteq/test/RTPencode.cc
@@ -450,7 +450,10 @@ int main(int argc, char* argv[]) {
   CHECK_NOT_NULL(out_file);
   printf("Output file: %s\n\n", argv[2]);
   packet_size = atoi(argv[3]);
-  CHECK_NOT_NULL(packet_size);
+  if (packet_size <= 0) {
+     printf("Packet size %d must be positive", packet_size);
+     return -1;
+  }
   printf("Packet size: %i\n", packet_size);
 
   // check for stereo