Fix build with recent version of GCC (#2661)

Without this patch, the definition of the custom deleter would drop the attributes of the `fclose` function.

BUG=#2660

tensorflow/lite/micro/tools/benchmarking/generic_model_benchmark.cc

diff --git a/tensorflow/lite/micro/tools/benchmarking/generic_model_benchmark.cc b/tensorflow/lite/micro/tools/benchmarking/generic_model_benchmark.cc
index 9874a63..f398963 100644
--- a/tensorflow/lite/micro/tools/benchmarking/generic_model_benchmark.cc
+++ b/tensorflow/lite/micro/tools/benchmarking/generic_model_benchmark.cc
@@ -99,8 +99,13 @@
 }
 
 #if !defined(GENERIC_BENCHMARK_USING_BUILTIN_MODEL)
+
+struct FileCloser {
+  void operator()(FILE* file) { fclose(file); }
+};
+
 bool ReadFile(const char* file_name, void* buffer, size_t buffer_size) {
-  std::unique_ptr<FILE, decltype(&fclose)> file(fopen(file_name, "rb"), fclose);
+  std::unique_ptr<FILE, FileCloser> file(fopen(file_name, "rb"));
 
   const size_t bytes_read =
       fread(buffer, sizeof(char), buffer_size, file.get());