Reintroduce a vsync option for people with really bad drivers

src/citra/config.cpp

@@ -123,6 +123,8 @@ void Config::ReadValues() {
     Settings::values.use_frame_limit = sdl2_config->GetBoolean("Renderer", "use_frame_limit", true);
     Settings::values.frame_limit =
         static_cast<u16>(sdl2_config->GetInteger("Renderer", "frame_limit", 100));
+    Settings::values.use_vsync_new =
+        static_cast<u16>(sdl2_config->GetInteger("Renderer", "use_vsync_new", 1));
 
     Settings::values.render_3d = static_cast<Settings::StereoRenderOption>(
         sdl2_config->GetInteger("Renderer", "render_3d", 0));

src/citra/default_ini.h

@@ -112,6 +112,11 @@ shaders_accurate_mul =
 # 0: Interpreter (slow), 1 (default): JIT (fast)
 use_shader_jit =
 
+# Forces VSync on the display thread. Usually doesn't impact performance, but on some drivers it can
+# so only turn this off if you notice a speed difference.
+# 0: Off, 1 (default): On
+use_vsync_new =
+
 # Resolution scale factor
 # 0: Auto (scales resolution to window size), 1: Native 3DS screen resolution, Otherwise a scale
 # factor for the 3DS resolution