- backend update from GZDoom.

Fixes:
* do not strip 'filter' as a directory prefix.
* proper spacing for scaled sheet fonts.
* fix of transparent color in BMF fonts.
* fix restart button on error pane in Windows.
* do not skip over empty 'if's with a condition that would error out.

source/common/rendering/hwrenderer/data/hw_shadowmap.h

@@ -57,6 +57,11 @@ public:
 		mLights[index + 3] = r;
 	}
 
+	bool Enabled() const
+	{
+		return mAABBTree != nullptr;
+	}
+
 protected:
 	// Upload the AABB-tree to the GPU
 	void UploadAABBTree();