use sleep instead of usleep

x/1-4-Drawing/drawing.min.cpp

@@ -33,8 +33,8 @@ int main( int argc, char* argv[] ) {
     XMapRaised(display, window);
     XFlush(display);
 
-    // give server 10ms to get set up before sending drawing commands
-    usleep(10 * 1000);  
+    // give server time to setup
+    sleep(1);  
 
 
     // drawing demo with graphics context here ...