settings: add hardware shader related settings

src/core/settings.h

@@ -107,6 +107,9 @@ struct Values {
 
     // Renderer
     bool use_hw_renderer;
+    bool use_hw_shader;
+    bool shaders_accurate_gs;
+    bool shaders_accurate_mul;
     bool use_shader_jit;
     u16 resolution_factor;
     bool use_vsync;