Fix clang warning on unused variable

mark variable as used.

fixes https://github.com/official-stockfish/Stockfish/issues/3900
closes https://github.com/official-stockfish/Stockfish/pull/3941

No functional change

src/evaluate.cpp

@@ -108,6 +108,7 @@ namespace Eval {
 
                 MemoryBuffer buffer(const_cast<char*>(reinterpret_cast<const char*>(gEmbeddedNNUEData)),
                                     size_t(gEmbeddedNNUESize));
+                (void) gEmbeddedNNUEEnd; // Silence warning on unused variable
 
                 istream stream(&buffer);
                 if (load_eval(eval_file, stream))