Fix clang warnings

DirectXMesh/DirectXMeshOptimizeLRU.cpp

@@ -285,7 +285,11 @@ namespace
                 vertexData.activeFaceListSize = 0;
             }
 
+#ifndef NDEBUG
             assert(curActiveFaceListPos == (indexCount - unused));
+#else
+            std::ignore = unused;
+#endif
         }
 
         // sort unprocessed faces by highest score

DirectXMesh/DirectXMeshP.h

@@ -57,6 +57,7 @@
 #pragma clang diagnostic ignored "-Wcovered-switch-default"
 #pragma clang diagnostic ignored "-Wfloat-equal"
 #pragma clang diagnostic ignored "-Wreserved-id-macro"
+#pragma clang diagnostic ignored "-Wundef"
 #endif
 
 #ifdef _WIN32