Revert "(Cg) Take out second_pass_shader / FBO functionality - everything"

This reverts commit deeaf981f7.

gfx/shader_cg.c

@@ -488,8 +488,22 @@ static bool load_plain(const char *path)
       if (!load_program(1, path, true))
          return false;
 
-      prg[2] = prg[0];
+      if (*g_settings.video.second_pass_shader
-      cg_shader_num = 1;
+#ifndef RARCH_CONSOLE
+            && g_settings.video.render_to_texture
+#endif
+         )
+      {
+         if (!load_program(2, g_settings.video.second_pass_shader, true))
+            return false;
+
+         cg_shader_num = 2;
+      }
+      else
+      {
+         prg[2] = prg[0];
+         cg_shader_num = 1;
+      }
    }
    else
    {