diff --git a/contrib/bobtoolz/DPatch.cpp b/contrib/bobtoolz/DPatch.cpp
index 5916d7e0..be49df4e 100644
--- a/contrib/bobtoolz/DPatch.cpp
+++ b/contrib/bobtoolz/DPatch.cpp
@@ -302,7 +302,7 @@ DPatch* DPatch::MergePatches( patch_merge_t merge_info, DPatch *p1, DPatch *p2 )
 
 	int newHeight = p1->height + p2->height - 1;
 	if ( newHeight > MAX_PATCH_HEIGHT ) {
-		return nullptr;
+		return NULL;
 	}
 
 	DPatch* newPatch = new DPatch();