gl_rasterizer: Emulate viewport flipping with ARB_clip_control

Emulates negative y viewports with ARB_clip_control. This allows us to
more easily emulated pipelines with tessellation and/or geometry shader
stages. It also avoids corrupting games with transform feedbacks and
negative viewports (gl_Position.y was being modified).

src/yuzu/main.cpp

@@ -817,6 +817,9 @@ QStringList GMainWindow::GetUnsupportedGLExtensions() {
     if (!GLAD_GL_ARB_multi_bind) {
         unsupported_ext.append(QStringLiteral("ARB_multi_bind"));
     }
+    if (!GLAD_GL_ARB_clip_control) {
+        unsupported_ext.append(QStringLiteral("ARB_clip_control"));
+    }
 
     // Extensions required to support some texture formats.
     if (!GLAD_GL_EXT_texture_compression_s3tc) {