LibGL+LibSoftGPU: Implement GL_POLYGON_OFFSET_FILL capability

Author: https://github.com/gmta
Commit: 453f62c935
Pull-request: https://github.com/SerenityOS/serenity/pull/12017
Reviewed-by: https://github.com/bgianfo ✅

Userland/Libraries/LibSoftGPU/Device.h

@@ -66,6 +66,7 @@ struct RasterizerOptions {
     bool enable_color_write { true };
     float depth_offset_factor { 0 };
     float depth_offset_constant { 0 };
+    bool depth_offset_enabled { false };
     bool enable_culling { false };
     WindingOrder front_face { WindingOrder::CounterClockwise };
     bool cull_back { true };