Add workaround for darwin SDL blank window bug

gui/gui.go

@@ -215,6 +215,8 @@ func (gui *GUI) Render() error {
 	startTime := time.Now()
 	showMessage := true
 
+	darwinRenderFixRequired := runtime.GOOS == "darwin"
+
 	for !gui.window.ShouldClose() {
 
 		select {
@@ -269,6 +271,12 @@ Buffer Size: %d lines
 
 			gui.window.SwapBuffers()
 
+			// Workaround for https://github.com/glfw/glfw/issues/1334
+			if darwinRenderFixRequired {
+				darwinRenderFixRequired = false
+				x, y := gui.window.GetPos()
+				gui.window.SetPos(x+1, y)
+			}
 		}
 
 	}