use dynamic scheduling in mandelbrot-openmp

mandelbrot-openmp.c

@@ -21,7 +21,7 @@ void drawmandelbrot(SDL_Surface * surface) {
   }
   Uint32 *pixels = (Uint32 *) surface->pixels;
 
-  #pragma omp parallel for
+  #pragma omp parallel for schedule(dynamic, 50000)
   for (int i = 0; i < surface->w * surface->h; i++) {
     int y = i / surface->w;
     int x = i % surface->w;