Avoid 100% CPU usage when calling ReadFromRFBServer and no available bytes to read

Signed-off-by: Vic Lee <llyzs@163.com>
Signed-off-by: Christian Beier <dontmind@freeshell.org>

libvncclient/sockets.c

@@ -150,6 +150,11 @@ ReadFromRFBServer(rfbClient* client, char *out, unsigned int n)
 	  errno=WSAGetLastError();
 #endif
 	  if (errno == EWOULDBLOCK || errno == EAGAIN) {
+#ifndef WIN32
+        usleep (10000);
+#else
+	 Sleep (10);
+#endif
 	    /* TODO:
 	       ProcessXtEvents();
 	    */
@@ -191,6 +196,11 @@ ReadFromRFBServer(rfbClient* client, char *out, unsigned int n)
 	  errno=WSAGetLastError();
 #endif
 	  if (errno == EWOULDBLOCK || errno == EAGAIN) {
+#ifndef WIN32
+        usleep (10000);
+#else
+	 Sleep (10);
+#endif
 	    /* TODO:
 	       ProcessXtEvents();
 	    */