patch 7.4.1890

Problem:    GUI: When channel data is received the cursor blinking is
            interrupted.  (Ramel Eshed)
Solution:   Don't update the cursor when it is blinking.

src/gui_photon.c

@@ -2232,6 +2232,12 @@ gui_mch_draw_part_cursor(int w, int h, guicolor_T color)
     DRAW_END;
 }
 
+    int
+gui_mch_is_blinking(void)
+{
+    return blink_state != BLINK_NONE;
+}
+
     void
 gui_mch_set_blinking(long wait, long on, long off)
 {