diff --git a/runtime/tests/test_gl_readback_region.c b/runtime/tests/test_gl_readback_region.c
index 7dfc6e63..355eebab 100644
--- a/runtime/tests/test_gl_readback_region.c
+++ b/runtime/tests/test_gl_readback_region.c
@@ -11,6 +11,7 @@ static int test_depth24;
 int gpu_display_is_depth24(void){return test_depth24;}
 void gpu_get_display_info(GpuDisplayInfo *out){memset(out,0,sizeof(*out));out->display_x=32;out->display_y=32;out->width=320;out->height=16;}
 int psx_ws_prim_in_backdrop(void){return 0;}
+int gpu_ws_nw_flat_backdrop_enabled(void){return 0;}
 int g_ws_tex_edge_pct=0;
 int psx_ws_prim_is_tagged(void){return 0;}
 void gpu_depth24_upload_span_reset(void){}