Move GL state utility mapping to renderer gl

docs/modernization/roadmap.md

@@ -453,6 +453,9 @@ and RGBA8 read/write pixel mapping to `pp_renderer_gl`.
 readback formats, sampler filters, depth/blend state, depth clears, viewport
 queries, color-mask booleans, active texture units, and float render-target
 formats to `pp_renderer_gl`.
+Legacy `util.cpp` OpenGL error naming and `gl_state` save/restore now delegate
+error codes, state queries, framebuffer targets, texture binding targets, and
+active texture units to `pp_renderer_gl`.
 The existing renderer classes are not yet fully
 behind the renderer interfaces.